VulnerabilityPublished 26 Feb 2026

CVE-2026-3268: PSI Probe · Improper Access Controls

Affects PSI ProbeSource CVE Database V5

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Public exploit available · CVSS 5.3 Medium.

Data as of 30 Oct 2026, 06:59 UTC

CVSS 4.0 base score

5.3Medium

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

EPSS: 0.2% chance of exploitation in 30 days – higher than 18% 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:L/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: Low
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: Low: Modification of data is possible, but the attacker does not have control over the consequence of a modification, or the amount of modification is limited. The data modification does not have a direct, serious impact to 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 29 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–
GitHubpsi-probe/psi-probe`pkg:github/psi-probe/psi-probe`Other threats	Affected 5.0 – 5.3.0 4 affected builds	Fixed in–

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

Given the absence of official patches, organizations should implement immediate compensating controls to mitigate risk. First, restrict network access to PSI Probe interfaces by limiting exposure to trusted internal networks or VPNs only. Employ strong authentication and authorization mechanisms around PSI Probe access points to prevent unauthorized users from reaching vulnerable endpoints. Monitor session activity and logs for unusual or unauthorized session attribute changes to detect potential exploitation attempts. Consider disabling or limiting the use of session attribute manipulation features within PSI Probe if feasible. Regularly update and audit Tomcat and PSI Probe configurations to minimize attack surface. Stay alert for vendor updates or community patches addressing this vulnerability and apply them promptly once available. Additionally, conduct security awareness training for administrators managing PSI Probe to recognize and respond to suspicious activity. Finally, consider deploying web application firewalls (WAFs) with custom rules to block suspicious requests targeting session attribute handlers.

Description

A vulnerability was detected in psi-probe PSI Probe up to 5.3.0. The affected element is an unknown function of the file psi-probe-core/src/main/java/psiprobe/controllers/sessions/RemoveSessAttributeController.java of the component Session Attribute Handler. Performing a manipulation results in improper access controls. The attack can be initiated remotely. The exploit is now public and may be used. The vendor was contacted early about this disclosure but did not respond in any way.

Impact

The improper access control vulnerability in PSI Probe can lead to unauthorized manipulation of session attributes, undermining the confidentiality and integrity of user sessions. Attackers could alter or remove session data, potentially hijacking sessions, escalating privileges, or disrupting normal application behavior. This can compromise sensitive information and trust in the monitored environment. Since PSI Probe is widely used for monitoring Apache Tomcat servers, organizations relying on it for session and server management may face increased risk of internal session tampering or external attacks exploiting this flaw. The medium severity rating indicates a moderate but tangible risk, especially in environments where session integrity is critical. The absence of vendor patches and public exploit availability increases the likelihood of exploitation attempts, potentially impacting organizations globally. The vulnerability could also serve as a stepping stone for more complex attacks targeting Tomcat infrastructure.

Summary

CVE-2026-3268 identifies an improper access control vulnerability in the PSI Probe application, specifically affecting versions 5.0 through 5.3.0. The vulnerability resides in the session attribute handler component, within an unspecified function of the RemoveSessAttributeController.java file. PSI Probe is a popular open-source monitoring tool for Apache Tomcat servers, providing insights into server status and session management. The flaw allows remote attackers with low privileges to manipulate session attributes without proper authorization checks, potentially altering or removing session data of other users. The vulnerability is exploitable remotely without user interaction or elevated privileges, increasing its risk profile. The CVSS 4.0 base score is 5.3 (medium severity), reflecting the moderate impact on confidentiality and integrity, with no impact on availability. The vendor was notified but has not responded or issued a patch, and a public exploit exists, although no active exploitation has been reported. This vulnerability could enable attackers to interfere with session integrity, potentially leading to unauthorized access or privilege escalation within affected Tomcat environments monitored by PSI Probe. The lack of vendor response and patch availability heightens the urgency for organizations to implement compensating controls.

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 26 Feb 2026, 23:26 UTC

Technical details

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