CVE-2026-29186
CVE-2026-29186 — @backstage/plugin-techdocs-node: TechDocs Mkdocs Configuration Key Enables Arbitrary Code Execution
Backstage is an open framework for building developer portals. Prior to version 1.14.3, this is a configuration bypass vulnerability that enables arbitrary code execution. The @backstage/plugin-techdocs-node package uses an allowlist to filter dangerous MkDocs configuration keys during the documentation build process. A gap in this allowlist allows attackers to craft an mkdocs.yml that causes arbitrary Python code execution, completely bypassing TechDocs' security controls. This issue has been patched in version 1.14.3.
Published Updated Sources: cvelistV5, GitHub_M
Triage
Is it exploited, how likely is exploitation, what does it touch, and how severe do the scoring sources call it.
Exploitation
Unreported
no source claims exploitation
EPSS
1%
chance of exploitation in 30 days
CVSS base
7.7
HIGH
CISA SSVC assessment
Three decision points CISA publishes for the CVEs it assesses · SSVC 2.0.3. A stakeholder decision, not a severity score.
Exploitation
None
none · proof-of-concept · active
Automatable
No
can an attacker script all four kill-chain steps
Technical impact
Total
partial · total control of the vulnerable component
Affected scope
The catalog records vendors and products as separate lists, not pairs, so which product belongs to which vendor is not something this page can say.
Every base score collected
Sources score independently and disagree; each row says who scored it and under which version.
| Score | Version | Severity | Expl. | Impact | Source |
|---|---|---|---|---|---|
| 7.7 | CVSS 3.1 | HIGH | — | — | cvelistV5 |
Weakness & attack patterns
- CWE-434
- CWE-74
- CWE-791
Attack patterns reported against this CVE. The ATT&CK techniques below are inferred from its weakness class.
- T1574.010Hijack Execution Flow: ServicesFile Permissions Weakness
- T1562.003Impair Defenses: Impair Command History Logging
- T1574.006Hijack Execution Flow: Dynamic Linker Hijacking
Detection
Read off the CVSS vector and the weakness class. Starting points, not rules we have tested.
- Search application, proxy, and WAF logs for requests touching /plugin-techdocs-node.
References
6 on the record
- github.com/backstage/backstage/security/advisories/GHSA-928r-fm4v-mvrw
x_refsource_CONFIRM
- access.redhat.com/security/cve/CVE-2026-29186
vdb-entry, x_refsource_REDHAT
- bugzilla.redhat.com/show_bug.cgi?id=2445480
issue-tracking, x_refsource_REDHAT
- security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-29186.json
x_sadp-csaf-vex
- access.redhat.com/errata/RHSA-2026:9742
vendor-advisory, x_refsource_REDHAT
- access.redhat.com/errata/RHSA-2026:13826
vendor-advisory, x_refsource_REDHAT
Elsewhere on this site
Not in any source we poll
Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.
- No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
- No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
- No exploit packet captures, log samples, or incident case IDs supplied.