CVE-2026-26304: Permission Bypass in Playbook Run Creation
Vulnerability summary
CVE-2026-26304 is a medium (CVSS 4.3) Incorrect Authorization vulnerability in mattermost. EPSS estimates a 0.17% chance of exploitation in the next 30 days, higher than 6.2% of scored vulnerabilities.
Not severe (CVSS 4.3, network access); no exploitation reported by the 5 checked sources
Source freshness unavailable
How is this decided?Advisory lineage
Upstream 0 · Downstream 2 · Related 2Timeline
- 16-03-2026PublishedVulnerability first disclosed.
- 17-03-2026Last modifiedVulnerability information updated.
Description
Mattermost versions 11.3.x <= 11.3.0, 11.2.x <= 11.2.2 fail to verify run_create permission for empty playbookId, which allows team members to create unauthorized runs via the playbook run API. Mattermost Advisory ID: MMSA-2025-00542
CVSS metrics
3 scores · 3 sources · 1 version- OSV · GoEcosystem advisory · calculated4.3MediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N
- NVDNIST4.3MediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N
EPSS trend
Probability
0.17%
Chance of exploitation in the next 30 days
Percentile
6%
Versus all other CVEs
30-day change
Decrease -0.09 pp
From 0.25% on 04-10-2026
Known exploited
Compare KEV catalogs
CISA KEVNot in the CISA KEV catalog.
ENISA CNWNot in the ENISA CNW catalog.
CIRCLNot in the CIRCL catalog.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeAffected systems
Known conditions: network-reachable, low-privilege account, no user interaction (CVSS vector). Other conditions: not stated in public data.
Mattermost2 products
- mattermost11.3.0 | ≥ 11.2.0, ≤ 11.2.2
- mattermost_server≥ 11.2.0, < 11.2.3 | ≥ 11.3.0, < 11.3.1
Github.com/mattermost1 product
- mattermost-plugin-playbooks< 1.41.1-0.20260316224925-705f54a81841
2 vendors · 3 products
