CVE-2025-3230VulnerabilityPublished 30 May 2025

CVE-2025-3230: Mattermost · Incorrect Implementation of Authentication Algorithm

Affects MattermostSource CVE Database V5

Not known to be exploited · CVSS 5.4 Medium.

Data as of 26 Oct 2026, 08:30 UTC

CVSS 3.1 base score

5.4Medium

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

EPSS: 0.2% chance of exploitation in 30 days – higher than 12% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N

Attack Vector: Network
Attack Complexity: Low
Privileges Required: Low
User Interaction: None
Scope: Unchanged
Confidentiality: Low
Integrity: Low
Availability: None

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

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, 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: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: Low: The attacker is authorized with (i.e., requires) privileges that provide basic user capabilities that could normally affect only settings and files owned by a user. Alternatively, an attacker with Low privileges may have the ability to cause an impact only to non-sensitive resources.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: Low: There is some loss of confidentiality. Access to some restricted information is obtained, but the attacker does not have control over what information is obtained, or the amount or kind of loss is limited. The information disclosure does not cause a direct, serious loss to the impacted component.
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 on the impacted component.
Availability: None: There is no impact to availability within the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 30 May 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
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), the Metasploit, Exploit-DB and nuclei-templates index as of 26 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.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC 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
Mattermost Mattermost	Affected =10.7.0 =10.6.0 =10.5.0 =9.11.0	Fixed in–

AI-suggested

European organizations should immediately audit their Mattermost deployments to identify affected versions and upgrade to patched versions once available. In the absence of patches, organizations should implement compensating controls such as: 1) Manually revoking all personal access tokens associated with deactivated users through administrative interfaces or API calls. 2) Enforcing short token lifetimes and rotating tokens frequently to limit the window of exposure. 3) Enhancing monitoring and alerting for unusual token usage patterns, especially from deactivated accounts. 4) Implementing strict user deactivation workflows that include token revocation as a mandatory step. 5) Restricting token issuance privileges to trusted administrators and limiting token scopes to minimize potential damage. 6) Employing network-level access controls and multi-factor authentication to reduce the risk of token misuse. Additionally, organizations should review their incident response plans to include scenarios involving token misuse by deactivated users.

Description

Mattermost versions 10.7.x <= 10.7.0, 10.6.x <= 10.6.2, 10.5.x <= 10.5.3, 9.11.x <= 9.11.12 fails to properly invalidate personal access tokens upon user deactivation, allowing deactivated users to maintain full system access by exploiting access token validation flaws via continued usage of previously issued tokens.

Impact

For European organizations using Mattermost, this vulnerability poses a significant risk to internal communication confidentiality and data integrity. Since Mattermost is widely used for team collaboration, unauthorized access via lingering personal access tokens could lead to exposure of sensitive corporate information, intellectual property, or personal data protected under GDPR. The failure to revoke access upon user deactivation means that former employees, contractors, or compromised accounts could maintain persistent access, increasing insider threat risks and complicating incident response. This could result in data breaches, regulatory non-compliance penalties, and reputational damage. The medium CVSS score reflects that while exploitation requires some level of privilege, the lack of user interaction and remote exploitability make it a practical threat in environments where token management policies are not strictly enforced. The impact is particularly critical in sectors with stringent data protection requirements such as finance, healthcare, and government agencies within Europe.

CWE-303Incorrect Implementation of Authentication Algorithm (opens in a new tab)
Base weaknessOWASP Top 10 A07:2025: Authentication Failures (opens in a new tab)
The requirements for the product dictate the use of an established authentication algorithm, but the implementation of the algorithm is incorrect.
OWASP Cheat Sheets
OWASP Authentication (opens in a new tab)
OWASP ASVS 4.0.3
V2.8.5 (opens in a new tab)
V2.8.4 (opens in a new tab)
V9.2.3 (opens in a new tab)
Attack patterns
Reflection Attack in Authentication Protocol (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

mattermost.com/security-updates (opens in a new tab)

Community reviews

Loading reviews…

Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 8 Jul 2025, 16:13 UTC

WeaknessesCWE-303

Technical details

References

Community reviews

Related threats