Home

Description

Mattermost versions 11.5.x <= 11.5.1, 10.11.x <= 10.11.13, 11.4.x <= 11.4.3 fail to validate 7zip archive structure before processing which allows an authenticated attacker to cause server memory exhaustion and denial of service via uploading a specially crafted 7zip file with excessive folder declarations.. Mattermost Advisory ID: MMSA-2026-00573

PUBLISHED Reserved 2026-04-15 | Published 2026-05-18 | Updated 2026-05-18 | Assigner Mattermost




MEDIUM: 4.3CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L

Problem types

CWE-789: Memory Allocation with Excessive Size Value

Product status

Default status
unaffected

11.5.0 (semver)
affected

10.11.0 (semver)
affected

11.4.0 (semver)
affected

11.6.0
unaffected

11.5.2
unaffected

10.11.14
unaffected

11.4.4
unaffected

Credits

Juho Forsén finder

References

mattermost.com/security-updates (MMSA-2026-00573) vendor-advisory

cve.org (CVE-2026-6340)

nvd.nist.gov (CVE-2026-6340)

Download JSON