Mattermost vulnerable to excessive memory consumptionGHSA-w496-f5qq-m58j
MEDIUMFix: mattermost/mattermost#24429GHSA-w496-f5qq-m58j is a medium-severity (CVSS 5.3) Uncontrolled Resource Consumption vulnerability in github.com/mattermost/mattermost-server/v6. A fix is available for github.com/mattermost/mattermost-server/v6 — see the affected versions and patch details below.
Exploitation Status
No confirmed exploitation observed yet
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for GHSA-w496-f5qq-m58j.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
Where this sits among everything scored
Real-World Exposure
github.com/mattermost/mattermost-server/v6🐹github.com/mattermost/mattermost/server/v8🐹github.com/mattermost/mattermost/server/v8🐹github.com/mattermost/mattermost/server/v8Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.
Description
Mattermost fails to properly sanitize the request to /api/v4/redirect_location allowing an attacker, sending a specially crafted request to /api/v4/redirect_location, to fill up the memory due to caching large items.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/mattermost/mattermost-server/v6 | all versions | 7.8.12go get github.com/mattermost/mattermost-server/v6@v7.8.12 |
| 🐹Go | github.com/mattermost/mattermost/server/v8 | ≥ 8.0.0&&< 8.0.4 | 8.0.4go get github.com/mattermost/mattermost/server/v8@v8.0.4 |
| 🐹Go | github.com/mattermost/mattermost/server/v8 | ≥ 8.1.0&&< 8.1.3 | 8.1.3go get github.com/mattermost/mattermost/server/v8@v8.1.3 |
| 🐹Go | github.com/mattermost/mattermost/server/v8 | ≥ 9.0.0&&< 9.0.1 | 9.0.1go get github.com/mattermost/mattermost/server/v8@v9.0.1 |
Affected Products
mattermostmattermostDetection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/mattermost/mattermost-server/v6, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update github.com/mattermost/mattermost-server/v6 to 7.8.12 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-w496-f5qq-m58j is resolved across your whole dependency graph.
Workarounds
Cap what an attacker can consume: apply request size, rate and timeout limits in front of the affected component, and run it with memory and CPU limits so exhaustion degrades one worker rather than the whole service.
Frequently Asked Questions
Is GHSA-w496-f5qq-m58j in your dependencies?
Find it across Go, including transitive dependencies.