Denial of Service via multiple identical User IDs in /api/v4/users/ids
Priority LOW 30CWE-400Published · Updated
Key facts
- Attack vector
- Network
- Privileges required
- Low
- User interaction
- None
- Attack complexity
- Low
- Impact type
- Denial of service
- Confidentiality · integrity · availability
- None · None · High
- Fix status
- Fixed
Attack profile from CVSS 3.1 · NVD. Fix status from CNA. Impact type from CWE-400.
Summary
Mattermost fails to deduplicate input IDs allowing a simple user to cause the application to consume excessive resources and possibly crash by sending a specially crafted request to /api/v4/users/ids with multiple identical IDs.
Why it matters now
Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00595 48th percentileScored 2026-11-07
Fix Fixed Mattermost (Mattermost): 7.8.11, 8.0.3, 8.1.2
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
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| Mattermost | Mattermost | up to 7.8.10; up to 8.0.2; up to 8.1.1 | 7.8.11, 8.0.3, 8.1.2 | Patch available | CNA |
- Mattermost VendorMattermost Affected up to 7.8.10; up to 8.0.2; up to 8.1.1 Fixed in 7.8.11, 8.0.3, 8.1.2 Patch available CNA
CPE configurations NVD · 1
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:* | before 7.8.11; 8.0.0 to before 8.0.3; 8.1.0 to before 8.1.2 | Vulnerable | Mattermost |
- cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:* Versions before 7.8.11; 8.0.0 to before 8.0.3; 8.1.0 to before 8.1.2 Vulnerable ·Mattermost
Remediation
- Fix · CNA Mattermost (Mattermost) Fixed in 7.8.11, 8.0.3, 8.1.2
Timeline
- 2026-10-02 Threatist record created from CVE-2023-5333
- 2026-10-03 Alias added: GHSA-w28r-7qw2-ghqc
References
Advisory 1
More Mattermost Server vulnerabilities
- 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
Sources
- CVE-2023-5333 · CVE Program
- CVE-2023-5333 · NVD
- FIRST EPSS
- GHSA-w28r-7qw2-ghqc · GitHub Advisory Database · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences