Yesterday, two critical vulnerabilities were disclosed in PHP, the scripting language used by many websites and online services: CVE-2026-109618 and CVE-2026-109619. Attackers can exploit them to remotely execute commands on any server running PHP, with no authentication required. The exploit has been dubbed PHP2Shell.
The PHP security team announced an upcoming emergency update on October 20 and released patches fixing the vulnerabilities the following day.
Nearly 70% of websites run on PHP, including services we use every day: wikis, online stores, smart devices with web interfaces, home network-attached storage (NAS), smart-home controllers, and much more.
Today, we explain how these vulnerabilities could affect you personally and what you can do to reduce the risks.
How the vulnerabilities can affect home users
Account and personal-data theft
The vulnerability allows an attacker to steal authentication tokens from server memory. These tokens essentially act like electronic passes โ telling a website that the user has already signed in. As a result, an attacker may be able to access someone elseโs account without entering a password or two-factor authentication code, putting messages, documents, delivery addresses, order histories, and other confidential information at risk.
Loss of files on home devices
If you have network-attached storage (NAS) or a video surveillance system at home that uses a vulnerable PHP version, it may also be at risk. Depending on what level of access they gain, attackers could potentially copy, delete or encrypt files they can access.
Malware infection
If an attacker gains access to a vulnerable website, they can use it in virtually any way they want: trick visitors into downloading a malicious file or clicking on a phishing link, display dangerous instructions, replace payment forms or login pages with malicious ones โ the list goes on and on. As a result, someone visiting a legitimate website could not only lose access to their account, but also lose money or accidentally infect their device with malware.
Below are examples of services directly affected by the vulnerabilities.
Which services are affected by the PHP vulnerabilities
Jeedom
Jeedom is a smart-home platform that lets users control lighting, sensors, heating, blinds and home IoT devices. Attackers could abuse this in many ways: they could disable the alarm, track when the homeowner is away, access video from the door intercom, and more.
The developers confirmed that the new vulnerability affects their application, and have already released an emergency update โ Jeedom 4.6.2. Users need to run the update twice for it to work. The developers say a fully fixed version for home users will be released in the coming days.
Websites we use every day
As mentioned above, PHP is used by roughly 70% of websites. This doesnโt mean every one of them is vulnerable: it depends on the PHP version in use and whether the site owners have already updated it. Many government websites in Europe have already suspended operations because of the new vulnerability.
Unfortunately, a website may still be vulnerable even if it appears to be working normally. An attacker could potentially take control of any legitimate website whose server hasnโt been patched yet. They could fake payment or login pages, host malicious files, or persuade users to download an โurgent updateโ that is actually malware.
Ordinary users have no reliable way to check whether such instructions or files are safe, so be sure to use reliable anti-phishing and antivirus protection. If you suspect that your data may have been stolen, check the active sessions in your account settings. If you spot suspicious activity or devices you donโt recognize, sign out of all active sessions and change your password. Use a password managerย โ it can generate a truly strong, unique password that you wonโt have to memorize yourself.
Computer games
Bad news for gamers: some video games whose servers use PHP are also at risk. If you donโt want attackers to get hold of your accounts, be sure to update the passwords for your gaming platforms, stores and accounts.
To buy time for updates, some developers temporarily took their services offline. Final Fantasy XIV, Pokemon Champions, games from Bandai Namco Entertainment, Uma Musume: Pretty Derby, Granblue Fantasy, Shadowverse: Worlds Beyond, and many others went into emergency maintenance. Nintendo Switch Online and the GOG and Steam stores were also affected.
Unfortunately, thereโve also been more drastic consequences. Yesterday, the developers of World Questannounced that the game would shut down permanently after 15 years: it relied on outdated infrastructure that would have been extremely difficult and costly to fix. For the same reason, the mobile game Please Save My Pandemonium! shut down after more than ten years of operation.
Home network-attached storage (NAS)
โHome cloudsโ have become popular in recent years for good reason: many users prefer to keep backups of their data at home rather than online. A number of companies make NAS devices, and at least three โ QNAP, Synology and ASUSTOR โ have said the vulnerabilities affect their products. An update has also been released for Unraid, an operating system for home servers, network storage and media servers.
QNAP
The manufacturer confirmed that the vulnerabilities affect several versions of its NAS operating systems โ QTS and QuTS hero โ as well as applications including QuMagie, Note Station 3 and certain versions of QVR Surveillance. A successful attack could put photos, documents, notes and camera recordings at risk.
At the time of publication of this blogpost, QNAP is still preparing updates, so the main priority is to temporarily disconnect NAS from the internet. QNAP recommends disabling port forwarding on the router โ to prevent NAS from automatically opening ports โ and allowing access to the management panel only from the home network orย through a VPN.
Synology
Both vulnerabilities have been officially confirmed in PHP packages 7.3, 7.4, and 8.0โ8.4, as well as in Mail Station and Synology Calendar. Fixes have already been released for PHP, starting from version 7.4, as well as for Mail Station and Synology Calendar. PHP 7.3 wonโt be fixed. The company separately notes that the PHP component built into its operating system cannot be reached from outside the device, so the risk of attack is very low.
ASUSTOR
ASUSTOR also officially confirmed both vulnerabilities, and immediately removed PHP 7, 7.3, 7.4, and 8.1 packages from App Central. The company recommends immediately backing up your data, removing older PHP packages, and using PHP 8.3 or 8.4.
Unraid
In todayโs operating-system update, PHP was upgraded to version 8.4.27 with fixes for the vulnerabilities. The developers recommend that all users update to Unraid 7.3.4. Containers with their own PHP installation must be updated separately: the new PHP version in the operating system doesnโt replace PHP inside containers.
At the time of publication, we havenโt found public confirmation from other major manufacturers (such as TerraMaster, UGREEN, Buffalo, or Western Digital) that their devices are affected by these vulnerabilities โ only user discussions on forums.
But the fact that only some NAS manufacturers have confirmed the problem so far doesnโt guarantee that your devices are safe โ especially if theyโre fairly old or come from a lesser-known or defunct manufacturer. In that case, first disconnect the devices from the internet while keeping them accessible only on the local network, and then investigate whether theyโre vulnerable.
Nextcloud cloud storage
Nextcloud is a free, open-source platform for creating your own cloud storage, serving as an alternative to Google Drive, Dropbox, and Microsoft OneDrive. It lets you store and synchronize files across devices, share them with other users, and work with documents, photos, calendars and contacts. The data can be stored on your own server or NAS rather than on a third-party companyโs servers.
If you store important data in Nextcloud, check how your cloud instance is configured. If you use Nextcloud All-in-One, update to version 14.4.1 where the vulnerability has already been fixed.
If your Nextcloud installation is configured differently, you need to update PHP yourself on the device or server.
How to protect your devices and data
Use phishing and malware protection. Our security solutionย automatically blocks phishing pages and malware, even when attackers place them on legitimate websites.
Keep an eye on updates. If you have network-attached storage, a smart-home system, a home server, a media server, or any other device with a web interface, first check the manufacturerโs website and install all available updates. If no update is available yet, temporarily disable internet access to the device.
Use strong passwords. Most people reuse the same password, or variations of it, across multiple websites. If an attacker finds one of those passwords on a vulnerable server, they may be able to compromise your other accounts as well. We recommend generating and storing strong, unique passwords in Kaspersky Password Manager so you donโt have to remember your credentials yourself. Be sure to enable two-factor authentication on all important accounts โ ideally using one-time codes generated by the same password manager.
Keep an offline backup of important files. Donโt rely on cloud storage alone โ make sure you keep a backup of all important documents on both a hard drive and an external device. For more information on how to make backups properly, see our article The internet remembers not quite everything.
What other risks can your home devices face? Read our articles:
Two critical vulnerabilities have been discovered in the popular PHP programming language. The vulnerabilities, identified as CVE-2026-109618 and CVE-2026-109619, allow attackers to remotely execute code on a server running PHP without authentication. The languageโs development team has released updates for all supported branches, but the first attempts to exploit the vulnerabilities were observed even before the patches were published. The exploit has been named PHP2Shell.
The architectures of popular marketplaces, e-commerce platforms, and learning management systems (LMS) are written in PHP. In addition, PHP is used in various content management systems (CMS) such as WordPress, Drupal, Joomla, and so on, which power most websites on the internet.
In this blogpost, we discuss CVE-2026-109618 and CVE-2026-109619 in detail, and explain how companies can protect their infrastructure. Read the Securelist expert blog to learn how events surrounding these vulnerabilities unfolded before the patch was released.
Vulnerable PHP versions
According to PHP web site, versions prior to 8.2.35, 8.3.36, 8.4.27, and 8.5.12 are vulnerable to CVE-2026-109618 and CVE-2026-109619. There are no official fixes for older branches. According to unofficial reports, the vulnerabilities also affect PHP versions starting with 5.4.0.
What makes CVE-2026-109618 and CVE-2026-109619 dangerous
Both vulnerabilities received a score of 9.2 on the CVSS v4.0 scale. They arise because, after a request is interrupted (for example, due to a memory shortage), PHP leaves invalid data in the memory buffer, and subsequently accesses it, allowing code to be executed on the server. One of the confirmed attack chains via CVE-2026-109619 exploits the `session.upload_progress` mechanism (which tracks file upload progress), which is enabled by default in PHP.
By exploiting these vulnerabilities, attackers can remotely execute code on the server with web server process privileges without authentication.
According to PHP developers, all installations of unpatched versions that process web requests are at risk, including PHP-FPM, Apache with mod_php, php-cgi, FrankenPHP, and LiteSpeed. The greatest risk lies with mod_php: researchers demonstrated an exploit for it in which an unauthenticated request triggers the attack even before the application code is executed.
What businesses should do
Weโve compiled key recommendations from the PHP developers and experts at Kaspersky.
Update PHP to versions 8.5.12, 8.4.27, 8.3.36, or 8.2.35. Start with systems accessible from the internet. The source code is available on the PHP website. If PHP is installed from distribution packages or provided by your hosting provider, check for updated packages: Linux distributions and LTS vendors received patches in advance. If the server is managed by a hosting provider, ask them to apply the update.
Versions 8.1 and older no longer receive updates from the PHP project. Check with your distribution vendor or LTS support provider to see if backported fixes are available, or switch to a supported branch. For PHP 7.4, 8.0, and 8.1, the developers have prepared minimal source code backports for manual compilation. These can also be found on the PHP website.
Restart PHP-FPM or the web server so that the processes load the new code, and verify the version using the `php -v` command. If PHP was installed from distribution packages, check the package changelog: the version number may remain the same.
Check the logs from October 20. A warning sign is when the web server process is performing actions it shouldnโt (running command shells, curl, wget, and the like). Kaspersky solutions help detect malicious activity in a timely manner. Attempts to exploit the described RCE vulnerabilities on Linux and Windows machines can be detected using Kaspersky NEXT EDR Expert, while exploitation of PHP2Shell in network traffic is detected by Kaspersky Anti Targeted Attack (KATA) with the NDR module.
If an immediate update is not possible
Only the immediate installation of patches will fully resolve the issue, but if that isnโt possible, itโs recommended to implement temporary measures. PHP developers provide step-by-step instructions for each vulnerability.
Not content with broken Windows updates, Microsoft has disclosed two problems with Defender for Endpoint on Linux โ one that could disable the security service after a reboot, and another that prevents updates on FIPS-enabled Red Hat Enterprise Linux 8 and 9. The more serious problem affected versions 101.26042.0000 through 101.26042.0009 across all supported Linux operating systems. After an upgrade or reinstall followed by a reboot, "the Defender service might be disabled on some devices," according to Microsoft. "If you use Defender for Servers (Plan 1 or 2) with Defender for Cloud and have the MDE [Microsoft Defender Endpoint] integration enabled, automatic updates for the MDE.Linux extension are enabled by default, which means your machines could have received an affected version automatically," it explained. "If an affected version was installed, the issue might impact active protection on rebooted devices until remediation steps are taken." Microsoft did not specify what caused Defender to become disabled, but anything that could knock out endpoint protection will give administrators sweaty palms. A separate problem affected RHEL 8 and 9 systems running in FIPS mode: the 101.26042.x update could fail to install, leaving devices on their previous version. FIPS refers to US Federal Information Processing Standards, which in this context impose requirements on the cryptography used by government and other regulated systems. Although Microsoft's alert did not mention an available update, its release notes direct users affected by the disabled-service bug to build 101.26042.0011. The separate FIPS installation problem is fixed in version 101.26052.0011 and later. Microsoft Defender for Endpoint on Linux protects server workloads on-premises and in the cloud. According to Microsoft, "it helps you prevent, detect, investigate, and respond to advanced threats with unified visibility through the Microsoft Defender portal." Other endpoint security platforms are available, but where an organization has gone all-in with Microsoft, the unified management offered by Defender for Endpoint on Linux can be difficult to resist. Microsoft has an unfortunate habit of shipping broken updates for its flagship operating system, Windows. An update that breaks software specifically designed to protect a device takes things to another level, particularly given the relentless rise in attacks and the need to both fend them off and monitor activity. Hence the appeal of unified visibility through the Microsoft Defender portal. However, an update that could leave Defender disabled after a reboot โ while also refusing to install on some security-hardened systems โ is less than ideal. ยฎ
Kremlin cyber goons have been breaking into government and commercial networks for at least a year by exploiting a Zimbra bug with a novel twist on Russiaโs usual phishing expeditions: this attack occurs as soon as the victim looks at an email, with no need to even click on a link or open a file. These attacks have been ongoing since July 2025, according to a whopping 27 US, UK, and other international government agencies, which attribute the intrusions to a group they track as Laundry Bear, aka Void Blizzard. โLaundry Bearโs targeting is almost certainly to gather sensitive information for the Russian Federation, with these actors primarily focusing on the covert acquisition of email data,โ according to the joint security alert. The Russiansโ latest campaign targets CVE-2025-66376, a cross-site scripting (XSS) vulnerability in the Zimbra web-based email and collaboration suite that was patched in November 2025 โ but Moscow's attackers began exploiting it long before then. This type of vulnerability allows attackers to inject malicious JavaScript into web pages viewed by the victim. In this case, the phishing bears abused the security hole in the Zimbra Collaboration Suite by sending malware-laden HTML email messages to target Western organizations. Targeted orgs include those in the defense industrial base, federal and local governments, education, energy, law enforcement, media, non-governmental organizations, and technology sectors. Some of the email addresses used in this campaign include ivanka.zurabishvili@proton[.]me, zmul1@buildandconsulting[.]com, garrysmithme@pinmx[.]net, and hostingclient@pinmx[.]net, weโre told. The attack doesnโt require any user interaction other than viewing the malicious email, and once that happens, the attackers get to work exfiltrating a ton of data. This includes the victimsโ last 90 days of email communications, email addresses and passwords, the organizationsโ email directories such as global address lists, two-factor authentication tokens, and newly created application passcodes. Then the attackers use these stolen credentials to maintain access to the victimsโ email, modifying account preferences and collecting authentication information. Laundry Bear stores the stolen goods on an unattributable virtual private server (VPS) running its custom โFlowerbedโ collection framework. Flowerbed is a Python project that uses Docker for containerization. โThe simplistic Flowerbed codebase has indications that artificial intelligence (AI) played a role in its development,โ the government agencies noted. The 31-page security alert includes an extensive indicators of compromise (IOC) section, which organizations should review to identify individuals compromised by the campaign. Also, the agencies recommend minimizing employeesโ use of the ZCS webmail client until their organizations update to a patched version that is not vulnerable to CVE-2025-66376. ยฎ