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Fencer Vulns
medium 6.8

CVE-2026-28741 json

CSRF Protection Bypass Allows Updating a User's Authentication Method

published 2026-04-15 6 mo ago modified 2026-06-25 4 mo ago also GHSA-m7cf-4gh2-v4qg , GO-2026-5495 , EUVD-2026-22875

cvss
6.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.1%
EPSS 0.1% chance of exploitation in 30 days, percentile 2%
public exploits
0
none known

Summary

Mattermost versions 10.11.x <= 10.11.12, 11.5.x <= 11.5.0, 11.4.x <= 11.4.2, 11.3.x <= 11.3.2 fail to validate CSRF tokens on an authentication endpoint which allows an attacker to update a user's authentication method via a CSRF attack by tricking a user into visiting a malicious page. Mattermost Advisory ID: MMSA-2026-00625

Patch / fix

  • go github.com/mattermost/mattermost/server/v8 8.0.0-20260220133927-c29cf05d40f8, 11.3.3, 11.4.3, 11.5.0
  • go github.com/mattermost/mattermost-server 11.3.3+incompatible, 11.4.3+incompatible, 11.5.0+incompatible
  • Mattermost Mattermost 10.11.13, 11.3.3, 11.4.3, 11.5.1
  • govulncheck-vulndb openSUSE Leap 16.0 0.0.20260723T184607-160000.1.1

opensuse advisories openSUSE-SU-2026:21483-1

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-28741 updated cvss 6.8

mattermost: CSRF protection bypass allows updating a user's authentication method

  • Red Hat All currently supported Red Hat products
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
total
Assessed
6 mo ago

Exploit prediction

0.13% chance of exploitation in the next 30 days, higher than 2% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 6.8 CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N
NVD 3.1 8.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N
GitHub 3.1 6.8 CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N

Affected packages

ecosystem package affected fixed in
go github.com/mattermost/mattermost/server/v8
>=8.0.0-20250721062209-4952acea88ce, <8.0.0-20260220133927-c29cf05d40f8
>=11.5.0-rc1, <11.5.0
>=11.4.0-rc1, <11.4.3
>=11.3.0-rc1, <11.3.3
8.0.0-20260220133927-c29cf05d40f8
11.5.0
11.4.3
11.3.3
go github.com/mattermost/mattermost-server
>=11.3.0-rc1+incompatible, <11.3.3+incompatible
>=11.4.0-rc1+incompatible, <11.4.3+incompatible
>=11.5.0-rc1+incompatible, <11.5.0+incompatible
11.3.3+incompatible
11.4.3+incompatible
11.5.0+incompatible
go github.com/mattermost/mattermost-server/v5
all versions
 no fix listed
go github.com/mattermost/mattermost-server/v6
all versions
 no fix listed

Affected products

  • Mattermost Mattermost

Classification

Weakness
  • CWE-352 Cross-Site Request Forgery

References

Sources

Fencer Vulns 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.