CVE-2026-10819: Mattermost versions 11.6.x <= 11.6.5, 10.11.x <= 10.11.20, 11.8.x <= 11.8.1, 11.7.x <= 11.7.4 fail to limit the number of frames and enforce the file size cap on animated GIF uploa
Mattermost versions 11.6.x <= 11.6.5, 10.11.x <= 10.11.20, 11.8.x <= 11.8.1, 11.7.x <= 11.7.4 fail to limit the number of frames and enforce the file size cap on animated GIF uploads, which allows an authenticated attacker to cause a denial of service via a crafted animated GIF uploaded as a custom emoji.. Mattermost Advisory ID: MMSA-2026-00695
Details
Original advisory: https://nvd.nist.gov/vuln/detail/CVE-2026-10819
Exploitation outlook
EPSS (FIRST.org) estimates each CVE’s probability of exploitation in the next 30 days — here is the CSIRTS.com read on those numbers.
- Low exploitation riskCVE-2026-108190.24% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 15% of all scored CVEs.
Referenced CVEs
| CVE | CSIRTS overview | External |
|---|---|---|
| CVE-2026-10819 | coverage & exploitation status | NVD · CVE.org |
Recent advisories for Mattermost
A cluster of recent advisories against the same product widens the attack surface — attackers routinely chain freshly published CVEs on one product, so review these together.
- mediumCVE-2026-7521: Mattermost versions 11.8.x <= 11.8.0, 11.7.x <= 11.7.3, 11.6.x <= 11.6.5, 10.11.x <= 10.11.20 f…nvd · 2026-07-28
- medium[UPDATE] [medium] Mattermost Server: Multiple vulnerabilitiescert-bund · 2026-07-28
- mediumCVE-2026-10600: Mattermost versions 11.8.x <= 11.8.0, 11.7.x <= 11.7.3, 11.6.x <= 11.6.5, 10.11.x <= 10.11.20 …nvd · 2026-07-27
- medium[NEW] [medium] Mattermost: Multiple vulnerabilities allow unspecified attackcert-bund · 2026-07-20
- unknownMultiple vulnerabilities in Mattermost Server (July 20, 2026)cert-fr-avis · 2026-07-20
- mediumCVE-2026-9602: Mattermost Desktop App versions <=6.2 6.0.2 5.6.13.0 fail to validate payloads sent from the Ma…nvd · 2026-07-17
More from NVD Recent CVEs
- mediumCVE-2026-67355: guzzlehttp/guzzle versions before 7.15.1 fail to preserve host-only cookie scope, storing the …2026-08-01
- mediumCVE-2026-67354: guzzlehttp/guzzle versions before 7.15.1 contain an information disclosure vulnerability in Re…2026-08-01
- mediumCVE-2026-67353: guzzlehttp/guzzle versions before 7.15.1 contain a denial of service vulnerability in the Cook…2026-08-01
- highCVE-2026-67352: luci-app-https-dns-proxy contains a stored cross-site scripting vulnerability in the resolver_…2026-08-01
- mediumCVE-2026-67344: ArcadeDB before 26.7.2 fails to enforce the UPDATE_SCHEMA database permission on the ALTER TYP…2026-08-01