CVE-2026-2457
Post Metadata Spoofing in Mattermost via Unsanitized PUT Requests
Publication date: 2026-03-16
Last updated on: 2026-03-18
Assigner: Mattermost, Inc.
Description
Description
CVSS Scores
EPSS Scores
| Probability: | |
| Percentile: |
Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| mattermost | mattermost_server | From 10.11.0 (inc) to 10.11.11 (exc) |
| mattermost | mattermost_server | From 11.2.0 (inc) to 11.2.3 (exc) |
| mattermost | mattermost_server | From 11.3.0 (inc) to 11.3.1 (exc) |
Helpful Resources
Exploitability
| CWE ID | Description |
|---|---|
| CWE-346 | The product does not properly verify that the source of data or communication is valid. |
Attack-Flow Graph
AI Powered Q&A
Can you explain this vulnerability to me?
This vulnerability exists in certain versions of Mattermost (11.3.x <= 11.3.0, 11.2.x <= 11.2.2, and 10.11.x <= 10.11.10) where the software fails to properly sanitize client-supplied post metadata.
Because of this, an authenticated attacker can craft PUT requests to the post update API endpoint that spoof permalink embeds, making it appear as if other users are impersonating those posts.
How can this vulnerability impact me? :
The impact of this vulnerability is that an authenticated attacker can impersonate other users by spoofing permalink embeds in posts.
This could lead to misinformation, confusion, or manipulation within the Mattermost communication platform, potentially damaging trust among users.
The CVSS score of 4.3 indicates a low to medium severity impact, specifically affecting integrity without impacting confidentiality or availability.
How does this vulnerability affect compliance with common standards and regulations (like GDPR, HIPAA)?:
I don't know
How can this vulnerability be detected on my network or system? Can you suggest some commands?
I don't know
What immediate steps should I take to mitigate this vulnerability?
I don't know