Reflected XSS in OAuth flow completion endpoints
Priority LOW 27CWE-79Published · Updated
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- Required
- Attack complexity
- Low
- Impact type
- Cross-site scripting
- Confidentiality · integrity · availability
- Low · Low · None
- Fix status
- Fixed
Attack profile from CVSS 3.1 · NVD. Fix status from CNA. Impact type from CWE-79.
Summary
A reflected cross-site scripting vulnerability in the OAuth flow completion endpoints in Mattermost allows an attacker to send AJAX requests on behalf of the victim via sharing a crafted link with a malicious state parameter.
Why it matters now
Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00413 35th percentileScored 2026-11-07
Fix Fixed Mattermost (Mattermost): 7.7
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 | 5.32.0 to before 7.7 | 7.7 | Patch available | CNA |
- Mattermost VendorMattermost Affected 5.32.0 to before 7.7 Fixed in 7.7 Patch available CNA
CPE configurations NVD · 1
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:* | 5.32.0 to before 7.7.0 | Vulnerable | Mattermost |
- cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:* Versions 5.32.0 to before 7.7.0 Vulnerable ·Mattermost
Remediation
- Fix · CNA Mattermost (Mattermost) Fixed in 7.7
Timeline
- 2026-10-02 Threatist record created from CVE-2023-1421
- 2026-10-03 Alias added: GHSA-mq63-cgjw-m94m
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-2023-1421 · CVE Program
- CVE-2023-1421 · NVD
- FIRST EPSS
- GHSA-mq63-cgjw-m94m · GitHub Advisory Database · CC BY 4.0
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