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VulnerabilityPublished

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

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Authoritative record:CVE-2026-52776· High 8.6

Not known to be exploited · CVSS 8.6 High : upgrade to 4.1.0 soon.

Data as of 12 Nov 2026, 23:24 UTC

CVSS 4.0 base score
8.6High
How severe the flaw is on the 0–10 CVSS scale.
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:N

Exploitation evidence

t = 0 is the CVE’s publication on cve.org

  1. Disclosed: evidence found.

    CVE published 25 Aug 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: evidence found.

    CISA SSVC: proof of concept public

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

Timeline

  1. CVE ID reserved

    by GitHub, Inc.

    , 78 days before disclosure

  2. CVE published

    on cve.org

    , t = 0

  3. 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

ProductAffectedFixed in
PyPIcompliance-trestleAffected
  • <4.1.0
Fixed in
  • 4.1.0

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

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.

References

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