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CVE-2026-87902: Critical Vulnerability in WordPress

25 September 2026 at 17:23

A critical vulnerability has been discovered in the popular WordPress content management system that allows attackers to execute arbitrary code on the web server. The vulnerability has been assigned the number CVE-2026-87902. The good news is that on September 22, WordPress released an update that patches it. The bad news is that the first attempts to exploit CVE-2026-87902 were detected just a few hours after the patch was released. Therefore, all companies whose corporate websites or blogs run on this platform are advised to update immediately.

WordPress versions affected by CVE-2026-87902

According to data published by WordPress on GitHub, all versions of the CMS from 4.7.0 through 7.1.1 are vulnerable. The company has released updates for all supported branches of the system; a complete table listing the patched version numbers can be found on the company’s GitHub page. The latest version of WordPress should be updated to version 7.1.2 (or newer).

What’s the nature of the CVE-2026-87902 vulnerability, and why is it so dangerous?

Under normal circumstances, WordPress loads PHP template files only from a specific folder within the active theme. However, due to the CVE-2026-87902 vulnerability, an attacker can craft a request to WordPress in such a way that an arbitrary PHP file is included — without requiring any authorization. Yes, the file must already be uploaded to the targeted server in some way, but that’s not really a problem for an attacker.

It sounds like a path traversal vulnerability, but in most publications, CVE-2026-87902 is classified as an RCE (Remote Code Execution) vulnerability because, under certain WordPress and PHP server configurations, the attack can lead to the execution of arbitrary code.

How to stay safe

The only way to secure a corporate WordPress site is to install the latest version. The researcher who discovered the vulnerability also offers several tips for hardening CMS security, but emphasizes that these are meant to complement the patch, not replace it.

The Hacker News lists several PHP filenames and IP addresses used in the attack via CVE-2026-87902. These can serve as indicators that a WordPress instance has been compromised.

Given that only a few hours pass between the publication of information about a vulnerability’s existence and the start of attacks exploiting it, it’s crucial for companies to have a properly configured, centralized vulnerability management system. To achieve this, they should have a specialized solution capable of identifying and resolving vulnerabilities, prioritizing them based on actual risks, and automating remediation processes. Our vulnerability management module for Kaspersky Next Optimum can help with this task.

Cybersecurity Tokenomics: Denial of Wallet Attacks | Kaspersky official blog

23 September 2026 at 16:40

Not long ago, many companies began actively implementing AI agents in a wide variety of workflows. Very quickly, the cost of using them became a pressing issue for companies. Moreover, it’s an issue that concerns more than just finance department — in addition to budgetary concerns, issues of reliability, operational stability, and even information security have emerged. This is because the cost of automating one and the same process varies significantly from one deployment to the next, is unpredictable, and could be subject to external influences.

Furthermore, for a malicious actor attacking an organization, any process automated using AI and vulnerable to external influence is, in essence, a convenient target for a “new type of DDoS attack”. Application-error reports, product reviews, or technical support requests can (just like any other external data that a company processes via AI) serve as a tool in an attack aimed at increasing consumption of tokens (word fragments that serve as the basic unit of input and output of an LLM).

A year of explosive growth… in bills

In 2026, large companies significantly overspent on their AI system budgets for the first time. Uber had spent its entire annual budget by April, while an unnamed company failed to set spending limits for Claude and spent $500 million in a single month. Although AI providers regularly announce lower prices and more efficient models, the shift from chatbots to agentic systems that operate continuously and autonomously increases token consumption by hundreds or thousands of times.  At the same time, the “fixed subscription for $20 or $100” model for companies is becoming a thing of the past; all major providers are transitioning business clients to pay-as-you-go billing.

As a result, companies are facing a problem all too familiar to cloud hosting and cellular communications industries. In the absence of specialized cost accounting and management systems, an organization only learns how much a particular process or project will cost after it’s completed. In the telecom and cloud sectors, this problem was eventually solved through the development of sophisticated billing systems, and their clients have even adopted the specialized term FinOps. For AI, this process is still in its infancy. Moreover, solving the problem will be complicated by the probabilistic nature of generative AI.

Unpredictable token consumption

To understand why costs rise so quickly and are so difficult to predict and control, we need to recall how a language model works and what turns it into an AI agent. The model is stateless; in other words, it does not retain any information between interactions. Every time the agent takes the next step, the entire history of work on a specific task (the context) must be resent to the model: the initial prompt, previous reasoning, the contents of the files it has read, and the responses from all tools. With each step, this “recap” grows longer — especially if the task involves iterative loops. If a step fails, or the response is unclear, or a tool returns an error, the agent simply tries again — further inflating the size of the context. And if the task is performed not by a single but by several agents, which divide the work among themselves and exchange results, this volume is multiplied by their number. As a result, token consumption does not increase gradually but in spurts, and it’s nearly impossible to predict it at the start of the task.

When running two different sessions of an AI agent interaction to solve exactly the same task (two tech-support tickets, two analytics tasks, and so on), the number of tokens spent on them can vary — the difference can be as much as 30 (!) times. This depends on how many steps, errors, and retries are required to solve the task. Increased resource consumption doesn’t necessarily depend on the complexity of the task. There are well-known cases where AI got stuck in a “thought loop” and wasted an absurd amount of resources on trivial tasks.

Three generations of AI in enterprise systems consume resources in completely different ways:

  • Classical machine learning (ML). This typically works with well-structured data and isn’t overly computationally intensive. Resource consumption is predictable and low. This is a fixed budget item;
  • A chatbot or other LLM-based AI assistant. It consumes tokens, but the pace is set by a human: an employee manually launches a task, then evaluates the result, and pauses. Cost increases roughly in proportion to the number of active users, and can be approximately estimated based on the number of licenses;
  • An autonomous AI agent. A person sets a goal and steps away, and the system then decides on its own what to do and how many steps are needed. The meter keeps ticking until the task is considered complete, and there’s no predictable cost ceiling.

Tokenomics in attacks: denial of wallet as the new DDoS

Since LLM calls are significantly more expensive than typical standard software calls, automating routine corporate tasks comes at an unusually high cost. For example, Gartner estimates that resolving a single customer support request using an LLM costs approximately $3. It’s easy to imagine how attackers could bombard a company with thousands of long, sophisticated requests generated by an inexpensive LLM, causing significant financial damage. Since the process is automated, anomalies may not be detected right away.

If an attacker knows which agent system and which LLM are used in a business process, they can carry out a more precise attack and cause significantly greater damage. The authors of the GitInject study estimated that an attacker capable of creating GitHub issues within an organization that uses AI agents for error analysis with single attack (before GitHub’s defense mechanisms kick in) can cause up to $111 in damage and burn through 400 minutes of GitHub Actions from the victim’s account. Naturally, such an attack can be repeated multiple times — at no cost to the attacker.

The most dangerous risk — though difficult to quantify in monetary terms — comes from attacks that provoke LLMs into excessive reasoning. In the paper OverThink, the authors demonstrated how a harmlessly worded task, when fed into a language model, ultimately yields a correct result but, in the process , consumes 46 (!) times more tokens than it should. Moreover, all tasks tested by the researchers successfully passed existing security filters.

In the new version of the OWASP Top Risks for Language Models guide, this issue has risen to a record-high priority: unbounded token consumption is now designated as LLM06:2026, and among its variations, the “denial of wallet” attack — which depletes the victim’s budget for LLMs — is explicitly highlighted.

How to Avoid Becoming a Victim of the “New DDoS”

First and foremost, you should abandon the principle of “using AI just for the sake of using AI”. It doesn’t make sense to entrust autonomous agents with every task. It’s wise to periodically conduct a cost-benefit analysis of using artificial intelligence.

In addition, you should limit the permissions and set of tools available to an autonomous AI agent. The fewer actions the system has access to, the more effectively it works on a narrow task, the fewer opportunities it has to inflate costs, and the less likely it is that someone will be able to “manipulate” it into unnecessary token spending.

We also recommend setting strict limits on token consumption, and configuring a notification system to alert humans when these limits are exceeded. It makes sense to implement multiple limits in parallel: a limit per task, a daily limit, and so on. Alerts regarding limit exceedances must be immediately forwarded to the specialist responsible for the system so that they can make an informed decision — whether to continue or halt the process.

Strictly verify external, untrusted data. Any information processed by AI that comes from external sources — whether it’s requests, inquiries, messages, or comments, or various technical fields capable of containing arbitrary text (DNS records, HTTP headers, filenames) — can not only lead to prompt injection, but also deliberately inflate the workload. It will be wise to limit their size and monitor the load they generate.

Calculate the unit cost of work and compare the vendor’s invoices with your own data. The cost per analysis, per request, or per check is the only way to understand what you’re paying for and to spot errors in the invoices.

Cybersecurity for SMBs: how to grow without the added risks

21 September 2026 at 17:23

Cybersecurity is often perceived in a highly formal, checkbox way: a mandatory line item in the budget, insurance against an attack, or an extra task for the IT team. But for SMBs, this approach doesn’t work well. As a company grows, so does its dependency on digital technology, which increases the number of potential entry points for attackers. Cloud services, business applications, extra devices for new hires: all of this generates new risks. Eventually, the question of how much to invest in cybersecurity gives way to a different one: how can it help the business grow without putting extra strain on the budget and staff? That’s the point where cybersecurity stops being just defense against threats, and instead becomes a driver of business growth.

The cost of a mistake

According to the new Global Kaspersky B2B Market Pulse survey, 86% of SMBs were hit by at least one cyberincident last year, while 25% of those incidents resulted in financial losses and business downtime. And it’s not always about a sophisticated targeted attack. Often the threat comes from employees’ everyday actions, such as using unverified software, personal devices, third-party AI services, or weak passwords. And since the IT team still has to handle its usual workload, a vulnerability in the infrastructure can go unnoticed for a long time.

At a small company, the fallout from an incident can affect not just a single IT process, but virtually the entire business — with disastrous results: employees can’t get any work done, customers get no services, data becomes unavailable, and the launch of a new project gets delayed. The company is forced to divert resources away from a growth focus to one of recovery. And that’s how an incident turns into a business risk.

More doesn’t mean better

At first glance, the solution seems obvious: if the number of threats keeps going up, businesses just need to deploy more security tools. But SMBs have another limiting factor: resources. In many companies, one small IT team juggles infrastructure, applications, cloud services, employee devices, and technical support. Cybersecurity becomes just another task on the list, often without a matching increase in headcount or expertise.

According to the mentioned survey, SMB and mid-market IT and security professionals themselves point out several internal constraints: a shortage of incident responders, heavy workloads on IT teams, delayed security investments, and rapid growth in the number of devices and services in use. This can create a vicious cycle: the business grows, the IT environment gets more complex, security becomes harder to manage, risks pile up, and security investment keeps getting pushed back until an incident finally happens.

An ounce of prevention is worth a pound of cure

After detecting an attacker in their infrastructure, companies typically scramble to reinforce several areas all at once: employee training, device security, monitoring, cloud security, and so on. According to the survey, оn average, businesses take action across 4.5 areas after an incident. This approach has an obvious drawback: the organization first suffers the consequences, and only then figures out what kind of protection it was missing in the first place. In other words, cybersecurity ends up being a reaction to something that’s already happened.

A more sustainable approach is to evolve a corporate security posture gradually and in sync with the business, anticipating changes in its infrastructure and processes. It’s not necessary to predict every possible threat. It’s enough for the IT team to regularly ask themselves a few practical questions:

  • Which technologies and systems does our business depend on today?
  • What’s changed in our IT environment?
  • Where are the biggest risks right now?
  • What can our team realistically keep under control?
  • What new security requirements will emerge at the next stage of growth?

Two paths for evolving corporate cybersecurity

When a company focuses on steadily building up its cybersecurity posture, two paths open up: raising its existing level of protection, and expanding coverage to address risks tied to new business needs. A business can pursue either path on its own or combine them.

Path 1: hardening protection

As a business and its security requirements mature, a company can move to more advanced levels of protection and, if needed, bring in managed services’ expertise. That’s exactly the approach behind Kaspersky Next Optimum — an offering for growing SMB and mid-market businesses. A small company may start with Kaspersky Next EDR Foundations, and later move up to the next protection tiers — EDR Optimum, XDR Optimum, or, if managed protection is needed, MXDR Optimum — as its security maturity grows.

Path 2: expanding coverage

Sometimes a company doesn’t need to move to a fundamentally different level of protection. It needs to solve a specific problem that came up as the business grew. For example, the company might ramp up its use of cloud infrastructure, discover that employees have become a major source of risk, or find itself needing to manage vulnerabilities systemically. In such cases, protection can be extended with Security Modules . They’re compatible with Kaspersky Next Optimum, and allow IT teams to cover specific needs as they emerge without having to replace the existing security foundation. Here are the key capabilities of each module:

  • Security Awareness helps reduce risks tied to the human factor, and turns employees into an extra layer of defense.
  • Email Security strengthens the protection of corporate communications and sensitive data against threats that spread through email.
  • Workload Security helps protect cloud and hybrid environments as businesses shift more of their workloads to the cloud.
  • Vulnerability Management lets IT teams identify and prioritize vulnerabilities to address them before attackers get the chance to exploit them.
  • Threat Lookup & Analysis provides extra context when investigating suspicious files, objects, and threat indicators.

Cybersecurity as a process: the benefits

Small and medium-sized businesses shouldn’t treat cybersecurity as a target to be reached and roll out every possible security tool all at once. It’s far more practical to treat it as an ongoing process closely tied to the company’s growth. This approach helps solve several problems simultaneously:

  1. Maintain business continuity. The sooner a threat is detected and stopped, the less likely it is to turn into a serious incident that disrupts the company’s operations. Protecting against threats, catching them early, and responding promptly all help lower the risk of downtime, and keep business processes running smoothly.
  2. Make the most of limited resources. Careful planning of corporate security strategy goes hand in hand with process automation, centralized visibility, and investigation tools. These, in turn, help cut down on routine tasks, and free up resources for what really matters.
  3. Build a foundation for future growth. By strengthening security as the business grows, the company builds a solid foundation for whatever comes next — whether that’s workload protection, more advanced vulnerability management, or deeper threat analysis. There’ll be no need to rebuild the defenses from scratch each time new business processes emerge.

Ultimately, well-built cybersecurity is more than just a tool for prevention and response. It’s what lets a company keep working despite a constantly growing number of threats, adopt new technology, seize new opportunities, and grow. Visit our website to learn more about how the Kaspersky Next Optimum and Security Modules help growing companies build protection that matches their current needs.

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