CVE-2026-6334

ℹ️ low

Summary

Mattermost versions 11.5.x <= 11.5.1, 10.11.x <= 10.11.13 fail to enforce client identity binding during the OAuth authorization code redemption flow which allows an authenticated OAuth client to redeem authorization codes issued to a different client via a crafted token exchange request.. Mattermost Advisory ID: MMSA-2026-00570

CVSS Score

3.1

Low

EPSS Score

0.0

Exploit Probability

Published Date

2026-05-18

First Seen: 2026-05-19

📊 Relative Risk Intelligence

This CVE is Lower Risk - more severe than 2.1% of all 326,604 vulnerabilities in our database.

#319,765

Below average severity

Severity Percentile

🎯 CISA SSVC Assessment Updated: May 18, 2026

🔍 Exploitation Status

None

No known exploits

⚙️ Automatable

Requires human interaction

💥 Technical Impact

Partial

Limited system impact

🏆 Discovered By

Dylan Haussermann

SSVC data provided by CISA

Last Modified 2026-05-29

Source NVD 🔗

CVSS Vector 3.1 CVSS:3.1/AV:N/AC:H/PR:H/UI:R/S:U/C:L/I:L/A:N

CWE IDs (Weakness Types)

CWE-305

📦 Affected Products 2

Vendor	Product	Status	Affected Versions
mattermost	mattermost_server	Affected	> 10.11.0 < 10.11.14
mattermost	mattermost_server	Affected	> 11.5.0 < 11.5.2

🔗 References 1

https://mattermost.com/security-updates

Vendor Advisory

🔗 Related CVEs 6

CVE ID	Severity	CVSS	EPSS	Summary	Published
CVE-2026-4915	🔶 medium	6.5	0.1	Mattermost versions 11.6.x <= 11.6.0, 11.5.x <= 11.5.3, 11.4.x <= 11.4.4, 10.11.x <= 10.11.14 fail to filter nil element...	2026-05-25
CVE-2026-3473	🔶 medium	5.9	0.0	Mattermost versions 11.6.x <= 11.6.0, 11.5.x <= 11.5.3, 11.4.x <= 11.4.4, 10.11.x <= 10.11.14 fail to validate file owne...	2026-05-22
CVE-2026-3636	🔶 medium	4.3	0.0	Mattermost versions 11.6.x <= 11.6.0, 11.5.x <= 11.5.3, 11.4.x <= 11.4.4, 10.11.x <= 10.11.14 fail to sanitize team memb...	2026-05-22
CVE-2026-4635	🔶 medium	6.5	0.0	Mattermost versions 11.6.x <= 11.6.0, 11.5.x <= 11.5.3, 11.4.x <= 11.4.4, 10.11.x <= 10.11.14 fail to archive the channe...	2026-05-22
CVE-2026-4646	🔶 medium	4.3	0.1	Mattermost versions 11.6.x <= 11.6.0, 11.5.x <= 11.5.3, 11.4.x <= 11.4.4, 10.11.x <= 10.11.14 fail to validate user-supp...	2026-05-22
CVE-2026-5308	🔶 medium	4.9	0.1	Mattermost versions 11.6.x <= 11.6.0, 11.5.x <= 11.5.3, 11.4.x <= 11.4.4, 10.11.x <= 10.11.14 fail to enforce request bo...	2026-05-22

These CVEs affect the same products