CVE-2025-55073Network attack vector

Arbitrary post edits via unbound OAuth redirect

Published Nov 14, 2025 · Updated Nov 14, 2025

Authorization bypass in Mattermost 10.5.0 through 10.5.11, 10.11.0 through 10.11.3, and 10.12.0 allows remote authenticated users to edit posts. The MS Teams plugin OAuth redirect handler accepts a crafted post identifier without confirming that the target post belongs to the OAuth flow being completed. A low-privileged account and a reachable, enabled MS Teams plugin OAuth flow are required; successful exploitation changes arbitrary post content and can impair its availability.

CVSS severity5.4
Medium
EPSS probability0.18%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Authorization bypass in Mattermost 10.5.0 through 10.5.11, 10.11.0 through 10.11.3, and 10.12.0 allows remote authenticated users to edit posts. The MS Teams plugin OAuth redirect handler accepts a crafted post identifier without confirming that the target post belongs to the OAuth flow being completed. A low-privileged account and a reachable, enabled MS Teams plugin OAuth flow are required; successful exploitation changes arbitrary post content and can impair its availability.

The record

CVE
CVE-2025-55073
Published
Nov 14, 2025
Updated
Nov 14, 2025
Vendor
Mattermost
Product
Mattermost
Classifications
CWE-306, T1565.001
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Nov 14, 2025CVE publishedPublication date reported by the CVE source.
  2. Nov 14, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=10.11.0 <=10.11.3
  2. Affected versionversion=10.12.0 <=10.12.0
  3. Affected versionversion=10.5.0 <=10.5.11

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Mattermost · Mattermostversion=10.11.0 <=10.11.3; version=10.12.0 <=10.12.0; version=10.5.0 <=10.5.11

Published CVSS scores

5.4Mattermost, Inc.CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:L
5.3NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-306Missing Authentication for Critical Function
T1565.001Stored Data Manipulation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo