VulnerabilityPublished 26 Feb 2026

CVE-2026-3269: PSI Probe · Denial of Service

Affects PSI ProbeSource CVE Database V5

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Public exploit available · CVSS 5.3 Medium.

Data as of 30 Oct 2026, 11:52 UTC

CVSS 4.0 base score

5.3Medium

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.6% chance of exploitation in 30 days – higher than 50% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:P

Base metrics

Attack Vector: Network
Attack Complexity: Low
Attack Requirements: None
Privileges Required: Low
User Interaction: None
Vulnerable system confidentiality: None
Vulnerable system integrity: None
Vulnerable system availability: Low
Subsequent system confidentiality: None
Subsequent system integrity: None
Subsequent system availability: None

Threat metrics

Exploit Maturity: POC

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable system is bound to the network stack and the set of possible attackers extends beyond the other options listed below, up to and including the entire Internet. Such a vulnerability is often termed “remotely exploitable” and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: The attacker must take no measurable action to exploit the vulnerability. The attack requires no target-specific circumvention to exploit the vulnerability. An attacker can expect repeatable success against the vulnerable system.
Attack Requirements: None: The successful attack does not depend on the deployment and execution conditions of the vulnerable system. The attacker can expect to be able to reach the vulnerability and execute the exploit under all or most instances of the vulnerability.
Privileges Required: Low: The attacker requires privileges that provide basic capabilities that are typically limited to settings and resources owned by a single low-privileged user. Alternatively, an attacker with Low privileges has the ability to access only non-sensitive resources.
User Interaction: None: The vulnerable system can be exploited without interaction from any human user, other than the attacker.
Vulnerable system confidentiality: None: There is no loss of confidentiality within the Vulnerable System.
Vulnerable system integrity: None: There is no loss of integrity within the Vulnerable System.
Vulnerable system availability: Low: Performance is reduced or there are interruptions in resource availability. Even if repeated exploitation of the vulnerability is possible, the attacker does not have the ability to completely deny service to legitimate users. The resources in the Vulnerable System are either partially available all of the time, or fully available only some of the time, but overall there is no direct, serious consequence to the Vulnerable System.
Subsequent system confidentiality: None: There is no loss of confidentiality within the Subsequent System or all confidentiality impact is constrained to the Vulnerable System.
Subsequent system integrity: None: There is no loss of integrity within the Subsequent System or all integrity impact is constrained to the Vulnerable System.
Subsequent system availability: None: There is no impact to availability within the Subsequent System or all availability impact is constrained to the Vulnerable System.
Exploit Maturity: POC: Based on threat intelligence sources each of the following must apply: · Proof-of-concept is publicly available · No knowledge of reported attempts to exploit this vulnerability · No knowledge of publicly available solutions used to simplify attempts to exploit the vulnerability

Definitions: FIRST CVSS v4.0 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 26 Feb 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: evidence found.
CVSS exploit maturity: proof of concept public
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), CVSS vector, the Metasploit, Exploit-DB and nuclei-templates index as of 30 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Affected software

Product	Affected	Fixed in
psi-probePSI Probe	Affected 5.0 – 5.3.0 4 affected builds	Fixed in–
Mavenpsi-probe/psi-probe`pkg:maven/psi-probe/psi-probe`Other threats	Affected 5.0 – 5.3.0 4 affected builds	Fixed in–

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AI-suggested

2) Employ web application firewalls (WAFs) or intrusion prevention systems (IPS) to detect and block suspicious requests targeting the ExpireSessionsController endpoint. 3) Monitor PSI Probe logs and server metrics for unusual activity or signs of resource exhaustion indicative of exploitation attempts. 4) Consider temporarily disabling or limiting session expiration features in PSI Probe if feasible to reduce attack vectors. 5) Keep PSI Probe updated and monitor vendor channels for any forthcoming patches or advisories. 6) As a longer-term solution, evaluate alternative monitoring tools or implement redundant monitoring to maintain visibility in case of PSI Probe service disruption. 7) Harden the underlying Tomcat server and associated infrastructure to minimize broader impact if PSI Probe is compromised.

Description

A flaw has been found in psi-probe PSI Probe up to 5.3.0. The impacted element is the function handleRequestInternal of the file psi-probe-core/src/main/java/psiprobe/controllers/sessions/ExpireSessionsController.java of the component Session Handler. Executing a manipulation can lead to denial of service. The attack can be launched remotely. The exploit has been published and may be used. The vendor was contacted early about this disclosure but did not respond in any way.

Impact

The primary impact of CVE-2026-3269 is the denial of service of the PSI Probe monitoring tool, which can lead to loss of visibility into Apache Tomcat server sessions and overall server health. This disruption can delay detection of other critical issues or attacks on the underlying infrastructure. Organizations relying on PSI Probe for real-time monitoring may experience operational blind spots, increasing risk exposure. Although the vulnerability does not directly compromise data confidentiality or integrity, the loss of monitoring capability can indirectly facilitate further attacks or prolonged outages. The ease of remote exploitation without user interaction and low privilege requirements increases the likelihood of attack attempts, especially in environments where PSI Probe is exposed to untrusted networks. The lack of vendor response and patches further exacerbates risk, potentially leading to increased downtime and operational impact in affected environments.

Summary

CVE-2026-3269 is a denial of service vulnerability identified in the PSI Probe monitoring tool, specifically affecting versions 5.0 through 5.3.0. The vulnerability resides in the handleRequestInternal method within the ExpireSessionsController.java file, part of the session handler component. PSI Probe is widely used to monitor Apache Tomcat servers, providing insights into server health and session management. The flaw allows a remote attacker to manipulate requests to this function, causing the application to enter a denial of service state, likely by exhausting resources or triggering unhandled exceptions. The attack vector requires no user interaction and can be executed remotely with low privileges, making it relatively easy to exploit. The CVSS 4.0 base score is 5.3, reflecting medium severity due to the lack of confidentiality, integrity, or availability impact beyond service disruption, and the requirement for some privileges. The vendor was notified early but has not issued a patch or response, and while no active exploitation in the wild is reported, a public exploit exists, increasing the urgency for mitigation. This vulnerability could disrupt monitoring operations, impacting administrators' ability to manage Tomcat server sessions effectively.

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 27 Feb 2026, 00:12 UTC

Technical details

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