High [CVE-2026-52776] Server-Side Request Forgery (SSRF) bypass via IPv4-mapped IPv6 and 0.0.0.0
This high-severity Red Hat Linux advisory covers CVE-2026-52776 affecting File Integrity Operator.
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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.
The URLSecurityValidator, intended to prevent Server-Side Request Forgery (SSRF), contains a bypass vulnerability. This bypass occurs because the validator does not properly handle IPv4-mapped IPv6 addresses or the unspecified address 0.0.0.0.
Affected product named by the advisory: File Integrity Operator.
- < 3.12.4
- < 4.0.0
- < 4.0.3
Official advisory · high-confidence parse· fetched 1 hour ago·verify at source
- 3.12.4
- 4.1.0
Official advisory · high-confidence parse· fetched 1 hour ago·verify at source
Mitigation
Upgrade to a fixed release: 3.12.4, 4.1.0. That is the remediation for this advisory.
The vendor advisory may list additional interim mitigations or workarounds not captured here — review it before change work.
Official advisory · high-confidence parse· fetched 1 hour ago·verify at source
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