CVE-2026-81714 in openssl-encrypt
Summary
by MITRE • 08/27/2026
openssl_encrypt (pip: openssl-encrypt) versions <= 1.4.8 use suffix-tolerant fingerprint matching in enroll_trust_key when binding a plugin-signing trust anchor. An operator who confirms a short (forgeable, ~32-bit) GPG key id could unknowingly enroll an attacker's colliding key as a trusted anchor, which then vouches for malicious plugins under the ENFORCE signature policy. Version 1.4.9 fixes this by requiring the confirmed value to exactly match the full primary-key fingerprint (case-insensitive, whitespace-stripped).
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Analysis
by VulDB Data Team • 08/27/2026
The openssl-encrypt Python package prior to version 1.4.8 contains a critical authentication bypass vulnerability rooted in its handling of GPG key fingerprints during the enrollment of trust anchors for plugin signing verification. The core technical flaw lies within the enroll_trust_key function, which implements suffix-tolerant fingerprint matching rather than requiring an exact match of the full primary-key fingerprint. In cryptographic systems relying on OpenPGP standards, such as those used by GNU Privacy Guard (GnuPG), key fingerprints are long hexadecimal strings that uniquely identify a public key pair. By accepting only a portion or suffix of this identifier for confirmation and binding purposes, the software introduces a significant collision risk. An attacker can exploit this weakness to perform a prefix or suffix collision attack, where they generate a malicious GPG key pair whose fingerprint shares the same truncated sequence as a legitimate, trusted anchor key that an operator intends to enroll.
This vulnerability directly impacts the integrity of the plugin signing verification process under ENFORCE signature policies. When an administrator confirms what appears to be a valid trust anchor by verifying only its short identifier, they may inadvertently bind their system to accept signatures from the attacker's colliding key as if it were the legitimate authority. Consequently, any plugins signed with the attacker's private key will pass validation checks because the public key associated with that signature matches the enrolled trust anchor based on the flawed suffix-matching logic. This effectively allows an adversary to distribute and execute malicious code within environments that rely on this package for security enforcement, undermining the fundamental assumption of authenticity provided by digital signatures. The operational impact is severe, as it compromises supply chain integrity and enables remote code execution or data exfiltration through seemingly trusted software updates.
From a classification perspective, this vulnerability aligns with CWE-295 Improper Certificate Validation, specifically regarding the failure to validate the full identity of a certificate or key before trusting its contents. It also relates to CWE-347 Improper Verification of Cryptographic Signature, as the system accepts signatures from an unauthorized entity due to insufficient uniqueness checks on the signing key identifier. In terms of the MITRE ATT&CK framework, this flaw facilitates techniques associated with T1195 Supply Chain Compromise and T1059 Command and Scripting Interpreter if malicious plugins are executed post-enrollment. The attack vector is primarily local or network-based depending on how trust anchors are distributed, but it requires initial interaction from a privileged user to confirm the key ID, making it an insider threat or social engineering risk as much as a technical exploit.
Mitigation strategies must prioritize immediate software updates and rigorous operational procedures. Organizations using openssl-encrypt should upgrade to version 1.4.9 or later without delay, as this release corrects the vulnerability by enforcing exact matching of the full primary-key fingerprint while allowing for case-insensitivity and whitespace stripping to accommodate minor formatting variations in user input. For environments where upgrading is not immediately feasible, administrators must manually verify that any enrolled trust anchors correspond exactly to their complete 40-character hexadecimal fingerprints rather than relying on shortened identifiers or suffixes displayed by default GPG tools. Additionally, implementing strict monitoring for changes in the list of trusted keys and auditing plugin signatures against known good baselines can help detect unauthorized enrollments. Security teams should also consider adopting multi-factor verification processes for critical trust anchor modifications to ensure that no single point of failure exists within the key enrollment workflow.