CVE-2026-52776: compliance-trestle has an URLSecurityValidator SSRF allowlist bypass via IPv4-mapped IPv6 and 0.0.0.0
Affects compliance-trestleSource GCVE Database
Not known to be exploited · CVSS 8.6 High : upgrade to 4.1.0 soon.
Data as of 12 Nov 2026, 23:24 UTC
- EPSS
- 0.4% chance of exploitation in 30 days – higher than 38% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 4.1.0
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:NExploitation evidence
t = 0 is the CVE’s publication on cve.org
Disclosed: evidence found.
CVE published 25 Aug 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: evidence found.
CISA SSVC: proof of concept public
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
Timeline
CVE ID reserved
by GitHub, Inc.
, 78 days before disclosure
CVE published
on cve.org
, t = 0
CISA SSVC assessment
proof of concept public
, 15 hours after disclosure
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), CISA SSVC, the Metasploit, Exploit-DB and nuclei-templates index as of 13 Nov 2026.
What to do
Upgrade compliance-trestle to 4.1.0.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| PyPIcompliance-trestle | Affected
| Fixed in
|
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AI-suggested
Upgrade compliance-trestle to version 4.1.0 or later, where the URLSecurityValidator properly normalizes IPv4-mapped IPv6 addresses, blocks the 0.0.0.0 address, and improves hostname checks to prevent SSRF allowlist bypass. Until upgrading, avoid processing untrusted OSCAL artifacts that may contain malicious URLs. No other vendor-recommended mitigations are documented.
Description
compliance-trestle version 4.0.3 contains an SSRF allowlist bypass vulnerability in its URLSecurityValidator component. The validator attempts to block requests to loopback, link-local, and cloud metadata IP ranges but fails to properly normalize IPv4-mapped IPv6 addresses and does not block the IPv4 unspecified address 0.0.0.0. This allows crafted URLs using these address forms to bypass the validator and reach restricted internal services. The vulnerability affects workflows that fetch OSCAL artifacts referencing such URLs, potentially exposing internal network resources. The issue is fixed in compliance-trestle version 4.1.0.