Mattermost up to 10.11.20/11.6.5/11.7.4/11.8.1 Animated GIF Upload denial of service

CVSS Meta Temp Score
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Current Exploit Price (≈)
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CTI Interest Score
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4.1$0-$5k2.09-

Summaryinfo

A vulnerability was found in Mattermost up to 10.11.20/11.6.5/11.7.4/11.8.1. It has been rated as problematic. This impacts an unknown function of the component Animated GIF Upload. This manipulation causes denial of service. This vulnerability is registered as CVE-2026-10819. Remote exploitation of the attack is possible. No exploit is available.

Detailsinfo

A vulnerability was found in Mattermost up to 10.11.20/11.6.5/11.7.4/11.8.1. It has been declared as problematic. Affected by this vulnerability is an unknown function of the component Animated GIF Upload. The manipulation with an unknown input leads to a denial of service vulnerability. The CWE definition for the vulnerability is CWE-404. The product does not release or incorrectly releases a resource before it is made available for re-use. As an impact it is known to affect availability. The summary by CVE is:

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

The advisory is shared at mattermost.com. This vulnerability is known as CVE-2026-10819 since 06/04/2026. The exploitation appears to be easy. The attack can be launched remotely. Neither technical details nor an exploit are publicly available. MITRE ATT&CK project uses the attack technique T1499 for this issue.

Upgrading to version 10.11.21, 11.6.6, 11.7.5, 11.8.2 or 11.9.0 eliminates this vulnerability.

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Productinfo

Type

Name

Version

License

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 4.3
VulDB Meta Temp Score: 4.1

VulDB Base Score: 4.3
VulDB Temp Score: 4.1
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AVACAuCIA
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Denial of service
CWE: CWE-404
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Mattermost 10.11.21/11.6.6/11.7.5/11.8.2/11.9.0

Timelineinfo

06/04/2026 CVE reserved
07/27/2026 +53 days Advisory disclosed
07/27/2026 +0 days VulDB entry created
07/27/2026 +0 days VulDB entry last update

Sourcesinfo

Advisory: mattermost.com
Status: Confirmed

CVE: CVE-2026-10819 (🔒)
GCVE (CVE): GCVE-0-2026-10819
GCVE (VulDB): GCVE-100-383425

Entryinfo

Created: 07/27/2026 16:39
Changes: 07/27/2026 16:39 (54)
Complete: 🔍
Cache ID: 216::103

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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