Unrated severityNVD Advisory· Published Jul 10, 2026· Updated Jul 13, 2026
Phalcon: Non-constant-time HMAC verification in `Encryption\Crypt::decrypt` (timing side-channel)
CVE-2026-54736
Description
Phalcon is a high-performance, full-stack PHP framework. Prior to 5.14.1, Phalcon\Encryption\Crypt::decrypt compares the attacker-supplied HMAC tag against the freshly computed HMAC using PHP/Zephir identity comparison, which lowers to a byte-wise comparison that returns early on the first differing byte. This observable timing discrepancy can allow an attacker to recover a valid tag byte-by-byte and attach it to a chosen IV and ciphertext so that decrypt() accepts tampered encrypted content as authentic. This issue is fixed in version 5.14.1.
Affected products
1Patches
Vulnerability mechanics
References
5- github.com/phalcon/cphalcon/commit/ad53ab1b2e7ec59b3af92b0b37b8aaa099011137mitrex_refsource_MISC
- github.com/phalcon/cphalcon/issues/17090mitrex_refsource_MISC
- github.com/phalcon/cphalcon/pull/17091mitrex_refsource_MISC
- github.com/phalcon/cphalcon/releases/tag/v5.14.1mitrex_refsource_MISC
- github.com/phalcon/cphalcon/security/advisories/GHSA-8jqh-95g6-7jpjmitrex_refsource_CONFIRM
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