Mattermost Server has Insufficient Session Expiration when used as an OAuth 2.0 service provider

published 2020-06-19 6y ago modified 2026-06-17 4mo ago also GHSA-g24c-fx4v-xg9w , GO-2026-4306 , EUVD-2017-9995

cvss: 5.3; version 3.1, NVD
cisa kev: Not listed; not in CISA's catalog
epss: 0.8%; EPSS 0.8% chance of exploitation in 30 days, percentile 56%
public exploits: 0; none known

An issue was discovered in Mattermost Server before 4.0.0, 3.10.2, and 3.9.2, when used as an OAuth 2.0 service provider, Session invalidation was mishandled.

Patch / fix

fixed in 2 distros 2 links 3

go github.com/mattermost/mattermost-server 3.9.2, 3.9.2+incompatible, 3.10.2, 3.10.2+incompatible
mattermost mattermost_server 3.9.2, 3.10.2

suse opensuse

govulncheck-vulndb openSUSE Leap 15.6 0.0.20260114T191543-150000.1.137.1

suse advisories SUSE-SU-2026:0142-1

govulncheck-vulndb openSUSE Leap 16.0 0.0.20260723T184607-160000.1.1

opensuse advisories openSUSE-SU-2026:21483-1

github.com/mattermost/mattermost@15ad24d commit
github.com/mattermost/mattermost@b17fca0 commit
github.com/mattermost/mattermost@fbc1707 commit

Is CVE-2017-18905 in your dependencies? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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Exploit prediction

0.78% chance of exploitation in the next 30 days, higher than 56% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by	version	score	vector
NVD	3.1	5.3	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
NVD	2.0	5.0	AV:N/AC:L/Au:N/C:N/I:P/A:N
GitHub	3.1	5.3	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

Affected packages

ecosystem	package	affected	fixed in
go	github.com/mattermost/mattermost-server	<3.9.2 >=3.10.0, <3.10.2 <3.9.2+incompatible >=3.10.0+incompatible, <3.10.2+incompatible	3.9.2 3.10.2 3.9.2+incompatible 3.10.2+incompatible

Classification

Weakness

CWE-613 DEPRECATED: Insufficient Session Expiration

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.