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TI-2026-80427 Aliases CVE-2026-93850GHSA-58rp-9f6f-pw76

Unbounded memory consumption during PDF text extraction in Mattermost

Priority LOW 29CWE-409Published · Updated

Key facts

Attack vector
Network
Privileges required
Low
User interaction
None
Attack complexity
Low
Impact type
—
Confidentiality · integrity · availability
None · None · High
Fix status
Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA.

Summary

Mattermost versions from 11.9.0 through 11.9.1, from 11.8.0 through 11.8.5, from 11.7.0 through 11.7.10, and from 11.10.0 through 11.10.1 fail to limit the volume of text extracted from an uploaded PDF. An authenticated user can upload a crafted PDF whose compressed content stream expands into a very large amount of text, exhausting server memory and causing a denial of service (CWE-409).

Written with Claude Haiku 5.5 from the sources below · 2026-10-28

Description from the CNA

Mattermost versions 11.9.x <= 11.9.1, 11.8.x <= 11.8.5, 11.7.x <= 11.7.10, 11.10.x <= 11.10.1 fail to bind the volume of text extracted from an uploaded PDF which allows an authenticated user to exhaust server memory and cause a denial of service via a crafted PDF whose compressed content stream expands into a very large amount of text.. Mattermost Advisory ID: MMSA-2026-00769

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00392 33rd percentileScored 2026-11-07
Fix Fixed Mattermost (Mattermost): 11.11.0, 11.9.2, 11.8.6 +2

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
MattermostMattermost11.9.0 – 11.9.1; 11.8.0 – 11.8.5; 11.7.0 – 11.7.10; 11.10.0 – 11.10.111.11.0, 11.9.2, 11.8.6, 11.7.11, 11.10.2Patch availableCNA
  • Mattermost VendorMattermost Affected 11.9.0 – 11.9.1; 11.8.0 – 11.8.5; 11.7.0 – 11.7.10; 11.10.0 – 11.10.1 Fixed in 11.11.0, 11.9.2, 11.8.6, 11.7.11, 11.10.2 Patch available CNA

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*11.7.0 to before 11.7.11; 11.8.0 to before 11.8.6; 11.9.0 to before 11.9.2; 11.10.0 to before 11.10.2VulnerableMattermost
  • cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:* Versions 11.7.0 to before 11.7.11; 11.8.0 to before 11.8.6; 11.9.0 to before 11.9.2; 11.10.0 to before 11.10.2 Vulnerable ·Mattermost

Remediation

Upgrade Mattermost to 11.11.0, 11.9.2, 11.8.6, 11.7.11 or 11.10.2, depending on the release line in use. Mattermost advisory MMSA-2026-00769 describes this issue. CISA has not listed this vulnerability in its Known Exploited Vulnerabilities catalog.

Written with Claude Haiku 5.5 from the sources below · 2026-10-28

  • Fix · CNA Mattermost (Mattermost) Fixed in 11.11.0, 11.9.2, 11.8.6, 11.7.11, 11.10.2

Timeline

  1. 2026-10-26 Threatist record created from CVE-2026-93850
  2. 2026-10-26 CISA SSVC decision points changed
  3. 2026-10-26 Priority changed: MEDIUM → LOW
  4. 2026-10-27 Alias added: GHSA-58rp-9f6f-pw76

References

Advisory 1

  • TI-2025-18933 Arbitrary file read in Mattermost Boards via import & export board archive CVSS 3.1CRITICAL 9.9
  • TI-2025-04465 Path Traversal Leading to RCE by Any Authenticated Mattermost User CVSS 3.1CRITICAL 9.9
  • TI-2017-14068 An issue was discovered in Mattermost Server before 3.6.2. CVSS 3.1CRITICAL 9.8
  • TI-2017-14060 An issue was discovered in Mattermost Server before 3.8.2, 3.7.5, and 3.6.7. CVSS 3.1CRITICAL 9.8
  • TI-2017-14048 An issue was discovered in Mattermost Server before 4.1.0, 4.0.4, and 3.10.3. CVSS 3.1CRITICAL 9.8
  • TI-2025-14360 Arbitrary file read via block duplication in Mattermost Boards CVSS 3.1CRITICAL 9.9
See all 505 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences