How severe is CVE-2026-1629?

CVE-2026-1629 has a CVSS 3.x base score of 4.3, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is low, integrity none, and availability none.

Is CVE-2026-1629 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (10th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-1629?

CVE-2026-1629 affects Mattermost Mattermost Server. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-1629?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

Does CVE-2026-1629 have an EU (EUVD) identifier?

Yes. CVE-2026-1629 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-12516.

When was CVE-2026-1629 published?

CVE-2026-1629 was published on 2026-03-16 and last updated on 2026-06-17.

CVE-2026-1629

CVE-2026-1629 is a medium-severity vulnerability in Mattermost Mattermost Server with a CVSS 3.x base score of 4.3. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-672.

Key facts

Severity: Medium (CVSS 3.x base score 4.3)
EPSS exploit prediction: 0% (10th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-12516
Weakness: CWE-672
Affected product: Mattermost Mattermost Server
Published: 2026-03-16
Last modified: 2026-06-17

Description

Mattermost versions 10.11.x <= 10.11.10 Fail to invalidate cached permalink preview data when a user loses channel access which allows the user to continue viewing private channel content via previously cached permalink previews until cache reset or relogin.. Mattermost Advisory ID: MMSA-2026-00580

Frequently asked questions

What is CVE-2026-1629?: Mattermost versions 10.11.x <= 10.11.10 Fail to invalidate cached permalink preview data when a user loses channel access which allows the user to continue viewing private channel content via previously cached permalink previews until cache reset or relogin.. Mattermost Advisory ID: MMSA-2026-00580
How severe is CVE-2026-1629?: CVE-2026-1629 has a CVSS 3.x base score of 4.3, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is low, integrity none, and availability none.
Is CVE-2026-1629 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (10th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-1629?: CVE-2026-1629 affects Mattermost Mattermost Server. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-1629?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2026-1629 have an EU (EUVD) identifier?: Yes. CVE-2026-1629 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-12516.
When was CVE-2026-1629 published?: CVE-2026-1629 was published on 2026-03-16 and last updated on 2026-06-17.

References

https://mattermost.com/security-updates

Affected products (1)

cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*

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