CVE-2026-52776 json
Trestle URLSecurityValidator SSRF allowlist bypass via IPv4-mapped IPv6 and 0.0.0.0
published 2mo ago modified 2mo ago also GHSA-h47f-gmjp-m7rr , PYSEC-2026-3659 , EUVD-2026-66210
- cvss
- 8.6
- version 4.0, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.4%
- EPSS 0.4% chance of exploitation in 30 days, percentile 38%
- public exploits
- 0
- none known
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.
Patch / fix
- pypi compliance-trestle 4.1.0
Is CVE-2026-52776 in your dependencies? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.
Check with FencerCISA SSVC
- Exploitation
- Proof of concept is public
- Automatable
- no
- Technical impact
- total
- Assessed
- 2mo ago
Exploit prediction
0.44% chance of exploitation in the next 30 days, higher than 38% of all scored CVEs (FIRST EPSS, 2026-11-11).
Exploits and checks
- github.com https://github.com/oscal-compass/compliance-trestle/security/advisories/GHSA-h47f-gmjp-m7rr referenced PoC, tagged "exploit" by a source, unverified
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 4.0 | 8.6 | CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N |
| CNA | 4.0 | 8.6 | CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X |
Affected packages
| ecosystem | package | affected | fixed in |
|---|---|---|---|
| pypi | compliance-trestle | <4.1.0 |
4.1.0 |
Affected products
- oscal-compass compliance-trestle
Classification
References
- github.com /oscal-compass/compliance-trestle/commit/5335ff873a2a68eb7de43df029bea09cadff22fd
-
github.com
/oscal-compass/compliance-trestle/commit/d107cd16efe8eb15d46be3c1d97f1ec73d32447c
web
-
github.com
/oscal-compass/compliance-trestle/security/advisories/GHSA-h47f-gmjp-m7rr
exploit, web
-
github.com
/oscal-compass/compliance-trestle
package
-
pypi.org
/project/compliance-trestle
package
-
github.com
/advisories/GHSA-h47f-gmjp-m7rr
advisory
-
nvd.nist.gov
/vuln/detail/CVE-2026-52776
advisory
Sources
- CVE List CVE-2026-52776
- GitHub Advisory GHSA-h47f-gmjp-m7rr
- NVD CVE-2026-52776
- OSV PYSEC-2026-3659
Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.