Cyber Resilience

CVE-2025-1412

Auth Bypass in Mattermost Server 9.11.0 – 9.11.7

Published
24 February 2025
Modified
01 October 2025
Patch / advisory
CVSS Score v3.1 3.1
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:N/A:N
EPSS Score 0.0025 16th percentile
Risk Priority 27 floored blend · peak EPSS

Summary

CVE-2025-1412 is a low-severity Session Fixation (CWE-384) vulnerability in Mattermost Mattermost Server. Its CVSS base score is 3.1 (Low).

Operationally, exploitation aligns with the MITRE ATT&CK technique Steal Web Session Cookie (T1539); ranked at the 16th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

The strongest mitigations our analysis identified map to SC-23 (Session Authenticity) and AC-12 (Session Termination) — see the control section below for these in your framework.

Deeper analysis AI-assisted summary

Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.

CVE-2025-1412 is a session management vulnerability affecting Mattermost versions 9.11.x up to and including 9.11.6 and 10.4.x up to and including 10.4.1. The flaw arises because the software fails to invalidate all active sessions when a user account is converted to a bot account. This issue, classified under CWE-384 (Session Fixation), has a CVSS v3.1 base score of 3.1 (AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:N/A:N) and was published on 2025-02-24.

A low-privileged user (PR:L) with network access (AV:N) can exploit this vulnerability if their account is converted to a bot, as their existing sessions remain valid despite the change. This allows the converted user to retain access with their original permissions while potentially gaining escalated privileges based on the permissions assigned to the new bot account. Exploitation requires high attack complexity (AC:H) and results in low confidentiality impact with no integrity or availability effects.

For mitigation details, refer to the official advisory at https://mattermost.com/security-updates, which provides guidance on patches and remediation steps for affected versions.

OWASP Top 10 for Web (2025)

EU & UK References

Vulnerability Data

Mattermost versions 9.11.x <= 9.11.6, 10.4.x <= 10.4.1 fail to invalidate all active sessions when converting a user to a bot, with allows the converted user to escalate their privileges depending on the permissions granted to the bot.

CWE(s)

Related Threats

MITRE ATT&CK Enterprise Techniques

T1539 Steal Web Session Cookie Credential Access
An adversary may steal web application or service session cookies and use them to gain access to web applications or Internet services as an authenticated user without needing credentials.
T1550.004 Web Session Cookie Lateral Movement
Adversaries can use stolen session cookies to authenticate to web applications and services.
T1606 Forge Web Credentials Credential Access
Adversaries may forge credential materials that can be used to gain access to web applications or Internet services.
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2026-9162Same product: Mattermost Mattermost Server
CVE-2023-1421Same product: Mattermost Mattermost Server
CVE-2026-3495Same product: Mattermost Mattermost Server
CVE-2023-1776Same product: Mattermost Mattermost Server
CVE-2023-7113Same product: Mattermost Mattermost Server
CVE-2026-6339Same product: Mattermost Mattermost Server
CVE-2026-2457Same product: Mattermost Mattermost Server
CVE-2023-3581Same product: Mattermost Mattermost Server
CVE-2025-9078Same product: Mattermost Mattermost Server
CVE-2024-36250Same product: Mattermost Mattermost Server

Affected Assets

mattermost
mattermost server
9.11.0 — 9.11.7 · 10.4.0 — 10.4.2

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

Detect
Catch it (NIST detect / respond)

Harden
Shrink the surface (DISA STIG)

Validate
Prove the fix (OWASP ASVS)
  • V4.4.4
  • V7.6.2

Mitigating Controls (NIST 800-53 r5) AI

Requires protection of session authenticity, which directly stops an attacker from using a stolen or fixed session identifier after authentication.

Limits the lifetime of any session (fixed or not), thereby reducing the window during which a stolen identifier remains usable.

Enforces that only properly authorized (i.e., freshly authenticated) sessions can access resources, making a pre-existing fixed session ID unusable.

Forces re-authentication under defined conditions, which should result in issuance of a fresh session identifier and invalidation of any prior one.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.AA-03 mostly match
prevents

Proper authentication processes must invalidate prior session identifiers to prevent fixation attacks.

PR.AA-01 partial match
prevents

Managing identities and credentials includes handling session identifiers as temporary credentials that must be invalidated on re-authentication.

PR.AA-04 partial match
prevents

Protecting and verifying identity assertions encompasses secure handling and regeneration of session tokens.

PR.PS-01 partial match
prevents

Configuration baselines can enforce session regeneration and timeout settings that block fixation.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

finds

Security testing can detect session-fixation issues, yet the weakness absence does not replace comprehensive testing.

degrades

Access-control policy can mandate session invalidation on re-authentication, but does not prescribe the technical mechanism.

degrades

Identity-management procedures can require new session tokens after login, yet the control is broader than session handling.

degrades

Authentication-information rules can include session-token lifecycle requirements, but the control focuses on credential management.

prevents

Secure-SDLC requirement can embed session-fixation checks, but eliminating the weakness does not satisfy the full SDLC control.

prevents

Application-security requirements can specify session handling, yet the weakness fix alone does not meet the broader requirement.

References