GHSA-fg35-5rf6-qg3g

GHSA-fg35-5rf6-qg3g PUBLISHED CVSS 5.699999809265137 MEDIUM

Record from GitHub Advisory Database · Published March 25, 2026

Mattermost allows attackers to take over arbitrary user accounts via overly permissive substring matching flaw

Fixed versions

Upgrade to a fixed version or later. Language registries are listed first, then Linux distributions, then vendor products.

Package	Ecosystem	Fixed in
github.com/mattermost/mattermost-server	Go Modules	11.4.1, 11.3.2, 11.2.4, 10.11.12
github.com/mattermost/mattermost/server/v8	Go Modules	8.0.0-20260217110922-b7d4a1f1f59b, 8.0.0-20260217110922

Risk scores

CVSS 3.1

5.699999809265137

CVSS:3.1/AV:N/AC:H/PR:H/UI:R/S:U/C:H/I:H/A:N

Affected products

Vendor	Product	Versions
github.com	mattermost/mattermost/server/v8
github.com	mattermost/mattermost-server	11.4.0-rc1, 11.3.0-rc1, 11.2.0-rc1

Timeline

Mar 25, 2026 CVE Published
Apr 9, 2026 Security Advisory

Query this with the API

The same record, from the CLI:

vulnetix vdb vuln GHSA-fg35-5rf6-qg3g
vulnetix vdb fixes GHSA-fg35-5rf6-qg3g

Or with curl, using the org id and key from your account page:

curl -s -H "Authorization: ApiKey ${VULNETIX_ORG_ID}:${VULNETIX_API_KEY}" \
  "https://api.vdb.vulnetix.com/v2/vuln/GHSA-fg35-5rf6-qg3g/fixes/registry"

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References

https://nvd.nist.gov/vuln/detail/CVE-2026-27656 advisory
https://github.com/mattermost/mattermost package
https://mattermost.com/security-updates url

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