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Fencer Intel
low 3.7

CVE-2026-4273 json

Insufficient token rotation validation in remote cluster invite confirmation

published 5mo ago modified 26d ago also GHSA-hqpj-f3jh-29vx , GO-2026-5432 , EUVD-2026-30740

cvss
3.7
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 3%
public exploits
0
none known

Summary

Mattermost versions 11.5.x <= 11.5.1, 10.11.x <= 10.11.13 fail to validate that the RefreshedToken differs from the original invite token during remote cluster invite confirmation which allows an authenticated attacker to bypass token rotation and reuse the original invite token via sending a crafted invite confirmation with a RefreshedToken matching the original token. Mattermost Advisory ID: MMSA-2026-00575

Patch / fix

  • go github.com/mattermost/mattermost/server/v8 8.0.0-20260313190740-742e0be95074, 10.11.14, 11.5.2
  • go github.com/mattermost/mattermost-server 5.3.2-0.20260313190740-742e0be95074, 10.11.14+incompatible, 11.5.2+incompatible
  • Mattermost Mattermost 10.11.14, 11.5.2, 11.6.0
  • govulncheck-vulndb openSUSE Leap 16.0 0.0.20260723T184607-160000.1.1

opensuse advisories openSUSE-SU-2026:21483-1

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CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
5mo ago

Exploit prediction

0.14% chance of exploitation in the next 30 days, higher than 3% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
CNA 3.1 3.7 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N
NVD 3.1 4.3 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N
GitHub 3.1 3.7 CVSS:3.1/AV:N/AC:H/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/v8
>=11.5.0, <11.5.2
>=10.11.0, <10.11.14
<8.0.0-20260313190740-742e0be95074
11.5.2
10.11.14
8.0.0-20260313190740-742e0be95074
go github.com/mattermost/mattermost-server
<5.3.2-0.20260313190740-742e0be95074
>=10.11.0+incompatible, <10.11.14+incompatible
>=11.5.0+incompatible, <11.5.2+incompatible
5.3.2-0.20260313190740-742e0be95074
10.11.14+incompatible
11.5.2+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

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.