Mattermost up to 11.9.x resource consumption

Summaryinfo

A vulnerability was found in Mattermost up to 10.11.22/11.7.7/11.8.4/11.9.0/11.9.x and classified as problematic. Affected is an unknown function. The manipulation results in resource consumption. This vulnerability is reported as CVE-2026-5132. The attack can be launched remotely. No exploit exists. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability was found in Mattermost up to 10.11.22/11.7.7/11.8.4/11.9.0/11.9.x. It has been classified as problematic. Affected is an unknown code. The manipulation with an unknown input leads to a resource consumption vulnerability. CWE is classifying the issue as CWE-400. The product does not properly control the allocation and maintenance of a limited resource, thereby enabling an actor to influence the amount of resources consumed, eventually leading to the exhaustion of available resources. This is going to have an impact on availability. CVE summarizes:

Mattermost versions 11.9.x <= 11.9.0, 11.8.x <= 11.8.4, 11.7.x <= 11.7.7, 10.11.x <= 10.11.22 fail to limit size of unpacked SDP messages compressed with zlib, which allows attacker to deny service or crash server via sending many SDP messages that unpack to large size.. Mattermost Advisory ID: MMSA-2026-00643

The advisory is shared for download at mattermost.com. This vulnerability is traded as CVE-2026-5132 since 03/30/2026. The exploitability is told to be easy. It is possible to launch the attack remotely. There are neither technical details nor an exploit publicly available. The MITRE ATT&CK project declares the attack technique as T1499.

Upgrading to version 10.11.23, 11.7.8, 11.8.5, 11.9.1 or 11.10.0 eliminates this vulnerability.

VulDB is the best source for vulnerability data and more expert information about this specific topic.

Productinfo

Type

• Groupware Software

Name

• Mattermost

Version

• 10.11.0
• 10.11.1
• 10.11.2
• 10.11.3
• 10.11.4
• 10.11.5
• 10.11.6
• 10.11.7
• 10.11.8
• 10.11.9
• 10.11.10
• 10.11.11
• 10.11.12
• 10.11.13
• 10.11.14
• 10.11.15
• 10.11.16
• 10.11.17
• 10.11.18
• 10.11.19
• 10.11.20
• 10.11.21
• 10.11.22
• 11.0
• 11.1
• 11.2
• 11.3
• 11.4
• 11.5
• 11.6
• 11.7
• 11.7.0
• 11.7.1
• 11.7.2
• 11.7.3
• 11.7.4
• 11.7.5
• 11.7.6
• 11.7.7
• 11.8
• 11.8.0
• 11.8.1
• 11.8.2
• 11.8.3
• 11.8.4
• 11.9
• 11.9.0

License

• open-source

CPE 2.3info

• 🔒
• 🔒
• 🔒

CPE 2.2info

• 🔒
• 🔒
• 🔒

CVSSv4info

CVSSv3info

CVSSv2info

Exploitinginfo

Threat Intelligenceinfo

Countermeasuresinfo

Timelineinfo

Sourcesinfo

Entryinfo

VulDB is the best source for vulnerability data and more expert information about this specific topic.

Discussion