CVE-2026-7511 in wolfSSL
Summary
by MITRE • 06/26/2026
PKCS7_verify signer confusion allows forged signatures, where the signer associated with a signature is not correctly bound, permitting a forged signature to be accepted.
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Analysis
by VulDB Data Team • 06/26/2026
The PKCS7_verify signer confusion vulnerability represents a critical flaw in cryptographic signature verification mechanisms that undermines the fundamental security guarantees of digital signatures. This vulnerability stems from improper binding between signature data and the signer identity within PKCS#7 formatted certificates and signed messages. The technical flaw occurs when the verification process fails to correctly associate the signature with its intended signer, creating opportunities for malicious actors to manipulate the verification logic and accept invalid signatures as legitimate. When a system processes a PKCS#7 signed message, it should validate that the signature was created by the claimed signer using the appropriate cryptographic keys and certificates. However, in the presence of this vulnerability, the verification routine may incorrectly accept signatures where the signer identity is not properly bound to the signature data, allowing an attacker to substitute their own signature for a legitimate one.
The operational impact of this vulnerability extends across numerous security-sensitive applications that rely on PKCS#7 signature validation for integrity and authenticity guarantees. Systems implementing cryptographic verification without proper signer binding can be exploited by adversaries to bypass authentication mechanisms in software update systems, code signing processes, certificate validation workflows, and secure communication protocols. The vulnerability particularly affects environments where multiple signers are present or when signature validation occurs in contexts where the expected signer identity is not properly enforced during verification. This flaw directly violates security principles outlined in the Common Weakness Enumeration catalog under CWE-347, which addresses improper certificate validation and authentication bypass vulnerabilities. The attack vector typically involves crafting malicious PKCS#7 messages with modified signer information that can pass through verification routines due to insufficient validation of the signature-to-signer relationship.
Security practitioners must recognize this vulnerability as a significant risk in cryptographic implementations and systems relying on X.509 certificates and PKCS#7 formatted signatures. The flaw aligns with techniques documented in the MITRE ATT&CK framework under the credential access and defense evasion domains, specifically targeting methods that manipulate authentication mechanisms through certificate and signature manipulation. Organizations should implement comprehensive validation of signer identity binding during signature verification, ensuring that all cryptographic operations properly verify that signature data corresponds to the claimed signer rather than accepting potentially forged signatures. Mitigation strategies include updating cryptographic libraries to versions with proper PKCS#7 verification logic, implementing additional checks for signer identity consistency, and deploying monitoring systems to detect anomalous signature validation behaviors. The vulnerability underscores the critical importance of proper certificate and signature validation practices in maintaining trust in digital security infrastructures, particularly in environments where software integrity and authenticity are paramount requirements for system security.