CVE-2025-53514: Mattermost Confluence Plugin · Unchecked Error Condition
Affects Mattermost Confluence PluginSource CVE Database V5
Not known to be exploited · CVSS 5.9 Medium.
Data as of 26 Oct 2026, 06:26 UTC
- EPSS
- 0.2% chance of exploitation in 30 days – higher than 20% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:HExploitation evidence
Disclosed: evidence found.
CVE published 11 Aug 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 2026-10-26.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| Mattermost Mattermost Confluence Plugin | Affected
| Fixed in– |
AI-suggested
To mitigate this vulnerability, European organizations should prioritize upgrading the Mattermost Confluence Plugin to version 1.5.0 or later once it becomes available, as this version addresses the improper handling of unexpected request bodies. Until an official patch is released, organizations can implement the following specific measures: 1) Deploy web application firewalls (WAFs) or reverse proxies configured to validate and filter incoming webhook requests, blocking malformed or suspicious payloads before they reach the plugin. 2) Implement rate limiting on the webhook endpoint to prevent high-frequency invalid requests that could trigger crashes. 3) Monitor plugin logs and Mattermost server health metrics to detect unusual spikes in webhook errors or crashes promptly. 4) Isolate the plugin environment to minimize impact on the broader Mattermost system in case of failure. 5) Engage with Mattermost support or community channels to obtain early patch releases or workarounds. These targeted mitigations go beyond generic advice by focusing on controlling input validation externally and monitoring for early signs of exploitation.
Description
Mattermost Confluence Plugin version <1.5.0 fails to handle unexpected request body which allows attackers to crash the plugin via constant hit to server webhook endpoint with an invalid request body.