Munged email address used for password resets and notifications
Priority LOW 28CWE-693Published · Updated
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- Security bypass
- Confidentiality · integrity · availability
- Low · Low · None
- Fix status
- Fixed
Attack profile from CVSS 3.1 · NVD. Fix status from CNA and GitHub. Impact type from CWE-693.
Summary
Mattermost versions 9.9.x <= 9.9.1, 9.5.x <= 9.5.7, 9.10.x <= 9.10.0 and 9.8.x <= 9.8.2 fail to ensure that remote/synthetic users cannot create sessions or reset passwords, which allows the munged email addresses, created by shared channels, to be used to receive email notifications and to reset passwords, when they are valid, functional emails.
Why it matters now
Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00261 18th percentileScored 2026-11-07
Fix Fixed Mattermost (Mattermost): 9.11.0, 9.9.2, 9.5.8 +2github.com/mattermost/mattermost/server/v8 (Go): 9.9.2, 9.5.8, 9.10.1 +1
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 | 9.9.0 – 9.9.1; 9.5.0 – 9.5.7; 9.10.0; 9.8.0 – 9.8.2 | 9.11.0, 9.9.2, 9.5.8, 9.10.1, 9.8.3 | Patch available | CNA |
| — | github.com/mattermost/mattermost/server/v8 (Go) | 9.9.0 to before 9.9.2 | 9.9.2 | Patch available | GHSA-c6vp-jjgv-38wj |
| — | github.com/mattermost/mattermost/server/v8 (Go) | 9.5.0 to before 9.5.8 | 9.5.8 | Patch available | GHSA-c6vp-jjgv-38wj |
| — | github.com/mattermost/mattermost/server/v8 (Go) | 9.10.0 to before 9.10.1 | 9.10.1 | Patch available | GHSA-c6vp-jjgv-38wj |
| — | github.com/mattermost/mattermost/server/v8 (Go) | 9.8.0 to before 9.8.3 | 9.8.3 | Patch available | GHSA-c6vp-jjgv-38wj |
- Mattermost VendorMattermost Affected 9.9.0 – 9.9.1; 9.5.0 – 9.5.7; 9.10.0; 9.8.0 – 9.8.2 Fixed in 9.11.0, 9.9.2, 9.5.8, 9.10.1, 9.8.3 Patch available CNA
- github.com/mattermost/mattermost/server/v8 (Go) Vendor— Affected 9.9.0 to before 9.9.2 Fixed in 9.9.2 Patch available GHSA-c6vp-jjgv-38wj
- github.com/mattermost/mattermost/server/v8 (Go) Vendor— Affected 9.5.0 to before 9.5.8 Fixed in 9.5.8 Patch available GHSA-c6vp-jjgv-38wj
- github.com/mattermost/mattermost/server/v8 (Go) Vendor— Affected 9.10.0 to before 9.10.1 Fixed in 9.10.1 Patch available GHSA-c6vp-jjgv-38wj
- github.com/mattermost/mattermost/server/v8 (Go) Vendor— Affected 9.8.0 to before 9.8.3 Fixed in 9.8.3 Patch available GHSA-c6vp-jjgv-38wj
CPE configurations NVD · 1
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:mattermost:mattermost:*:*:*:*:*:*:*:* | 9.5.0 to before 9.5.8; 9.8.0 to before 9.8.3; 9.9.0 to before 9.9.2; 9.10.0 to before 9.10.1 | Vulnerable | Mattermost |
- cpe:2.3:a:mattermost:mattermost:*:*:*:*:*:*:*:* Versions 9.5.0 to before 9.5.8; 9.8.0 to before 9.8.3; 9.9.0 to before 9.9.2; 9.10.0 to before 9.10.1 Vulnerable ·Mattermost
Remediation
- Fix · CNA Mattermost (Mattermost) Fixed in 9.11.0, 9.9.2, 9.5.8, 9.10.1, 9.8.3
- Fix · GHSA-c6vp-jjgv-38wj github.com/mattermost/mattermost/server/v8 (Go) Fixed in 9.9.2 Advisory →
- Fix · GHSA-c6vp-jjgv-38wj github.com/mattermost/mattermost/server/v8 (Go) Fixed in 9.5.8 Advisory →
- Fix · GHSA-c6vp-jjgv-38wj github.com/mattermost/mattermost/server/v8 (Go) Fixed in 9.10.1 Advisory →
- Fix · GHSA-c6vp-jjgv-38wj github.com/mattermost/mattermost/server/v8 (Go) Fixed in 9.8.3 Advisory →
Timeline
- 2026-10-02 Threatist record created from CVE-2024-39836
- 2026-10-03 Alias added: GHSA-c6vp-jjgv-38wj
References
More Mattermost vulnerabilities
- TI-2024-26695 Malicious remote can invite itself to an arbitrary local channel CVSS 3.1CRITICAL 9.6
- TI-2023-02056 Oauth authorization codes do not expire when deauthorizing an oauth2 app CVSS 3.1CRITICAL 9.1
- TI-2019-15069 An issue was discovered in Mattermost Mobile Apps before 1.26.0. CVSS 3.1CRITICAL 9.1
- TI-2024-26233 Malicious remote can add users to arbitrary teams and channels CVSS 3.1HIGH 8.7
- TI-2024-26746 Permanently local data deletion by malicious remote CVSS 3.1HIGH 8.7
- TI-2023-06508 Injection in Mattermost CVSS 3.1HIGH 8.8
Sources
- CVE-2024-39836 · CVE Program
- CVE-2024-39836 · NVD
- FIRST EPSS
- GHSA-c6vp-jjgv-38wj · GitHub Advisory Database · CC BY 4.0
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