Trestle URLSecurityValidator SSRF allowlist bypass via IPv4-mapped IPv6 and 0.0.0.0
Key facts
- Attack vector
- Network
- Privileges required
- Low
- User interaction
- None
- Attack complexity
- Low
- Attack requirements
- None
- Impact type
- —
- Confidentiality · integrity · availability
- High · High · None
- Fix status
- Fixed
Attack profile from CVSS 4.0 · CNA. Fix status from CNA and GitHub.
Summary
Compliance-trestle (Trestle) is a tooling platform for managing compliance as code. In versions before 3.12.4 and versions 4.0.0 through 4.0.3, the URLSecurityValidator that guards trestle's remote-fetch paths against server-side request forgery can be bypassed to reach loopback, link-local, cloud-metadata, and internal network endpoints it was designed to block. The blocklist does not canonicalize IPv4-mapped IPv6 literals such as [::ffff:169.254.169.254], which resolve to IPv6Address objects that never match the blocked IPv4 ranges, and it does not block the unspecified address 0.0.0.0, which routes to local services on Linux and inside containers. An attacker who can supply or influence an OSCAL artifact that trestle fetches, such as a malicious profile whose imports reference one of these bypass URLs, can cause the HTTPSFetcher and SFTPFetcher paths to contact cloud instance-metadata services, loopback interfaces, or internal hosts. This issue is fixed in versions 3.12.4 and 4.1.0.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- Poc
- Automatable
- No
- Technical impact
- Total
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 |
|---|---|---|---|---|---|
| oscal-compass | compliance-trestle | before 3.12.4; 4.0.0 to before 4.1.0 | 3.12.4, 4.1.0 | Patch available | CNA |
| — | compliance-trestle (PyPI) | before 4.1.0 | 4.1.0 | Patch available | GHSA-h47f-gmjp-m7rr |
- compliance-trestle Vendoroscal-compass Affected before 3.12.4; 4.0.0 to before 4.1.0 Fixed in 3.12.4, 4.1.0 Patch available CNA
- compliance-trestle (PyPI) Vendor— Affected before 4.1.0 Fixed in 4.1.0 Patch available GHSA-h47f-gmjp-m7rr
Remediation
- Fix · CNA compliance-trestle (oscal-compass) Fixed in 3.12.4, 4.1.0
- Fix · GHSA-h47f-gmjp-m7rr compliance-trestle (PyPI) Fixed in 4.1.0 Advisory →
Timeline
- 2026-10-02 Threatist record created from CVE-2026-52776
- 2026-10-03 Alias added: GHSA-h47f-gmjp-m7rr
References
Other 4
- https://github.com/oscal-compass/compliance-trestle/security/advisories/GHSA-h47f-gmjp-m7rr
- https://github.com/oscal-compass/compliance-trestle/commit/5335ff873a2a68eb7de43df029bea09cadff22fd
- https://github.com/oscal-compass/compliance-trestle/commit/d107cd16efe8eb15d46be3c1d97f1ec73d32447c
- https://github.com/oscal-compass/compliance-trestle
More oscal-compass vulnerabilities
- TI-2026-34065 compliance-trestle - jinja has an Arbitrary File Write via Path Traversal CVSS 3.1HIGH 8.4
- TI-2026-34145 compliance-trestle Vulnerable to Remote Code Execution via Recursive Server-Side Template Injection (SSTI) CVSS 3.1HIGH 7.8
- TI-2026-33511 compliance-trestle Profile Import has an Arbitrary File Read via trestle:// URI and Relative Path Traversal CVSS 4.0MEDIUM 6.9
- TI-2026-34095 compliance-trestle Vulnerable to SSRF in Remote Fetching Subsystem CVSS 3.1MEDIUM 6.7
- TI-2026-41137 Trestle SSTI in Jinja2 include tags allows arbitrary code execution (Incomplete fix of CVE-2026-46439) CVSS 3.1HIGH 7.8
- TI-2026-39563 Trestle has Server-Side Template Injection (SSTI) via Recursive Template Re-evaluation of Untrusted Data CVSS 3.1HIGH 7.8
Sources
- CVE-2026-52776 · CVE Program
- CVE-2026-52776 · NVD
- FIRST EPSS
- GHSA-h47f-gmjp-m7rr · GitHub Advisory Database · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences