Bug 2571746 (CVE-2026-64855)

Summary: CVE-2026-64855 soapbar: soapbar: Authentication bypass via untrusted certificate validation in verify_envelope_bsp
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerability-draftAssignee: Product Security <prodsec-ir-bot>
Status: NEW --- QA Contact:
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Priority: high    
Version: unspecifiedKeywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in soapbar. The verify_envelope_bsp() function establishes trust using an untrusted digital certificate embedded directly within the incoming message without validating it against a trusted Certificate Authority (CA) or an allowlist. A remote attacker can exploit this flaw by submitting a forged message signed with an attacker-controlled certificate, leading to an authentication bypass and user impersonation.
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Description OSIDB Bzimport 2026-11-11 15:51:13 UTC 
soapbar is a SOAP library for Python — client, server, and WSDL handling. Prior to version 0.13.0, verify_envelope_bsp() derived its trust anchor from the message it was verifying. It read the X.509 certificate out of the caller-untrusted wsse:BinarySecurityToken, validated only that certificate's not-before / not-after dates, and then verified the signature against that same certificate. There was no CA-chain validation, no issuer/subject allowlist, and no pinning. A successful verify_envelope_bsp() therefore proved only that the envelope was signed by whoever supplied the embedded certificate — never that it was signed by a trusted party. An attacker who mints their own certificate, signs a forged envelope, and embeds that certificate in the token passes verification. Any consumer that treats a successful BSP verification as authentication can be impersonated (signature forgery / authentication bypass). verify_envelope() (which pins a caller-supplied x509_cert) was not affected — the flaw was specific to the BSP variant whose trust anchor came from the message. This issue has been patched in version 0.13.0.