CVE-2026-54736 json
Phalcon: Non-constant-time HMAC verification in `Encryption\Crypt::decrypt` (timing side-channel)
published 2026-07-10 4 mo ago modified 2026-10-25 15 d ago also GHSA-8jqh-95g6-7jpj , EUVD-2026-43097
- cvss
- 8.2
- version 4.0, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.2%
- EPSS 0.2% chance of exploitation in 30 days, percentile 7%
- public exploits
- 0
- none known
Summary
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.
Patch / fix
- packagist phalcon/cphalcon 5.14.1
- github.com/phalcon/cphalcon@ad53ab1 commit
- github.com/phalcon/cphalcon#17091 pull request
- github.com/phalcon/cphalcon/releases/tag/v5.14.1 release
CISA SSVC
- Exploitation
- none
- Automatable
- no
- Technical impact
- partial
- Assessed
- 3 mo ago
Exploit prediction
0.18% chance of exploitation in the next 30 days, higher than 7% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 4.0 | 8.2 | 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 |
| CNA | 4.0 | 8.2 | 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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X |
Affected packages
| ecosystem | package | affected | fixed in |
|---|---|---|---|
| packagist | phalcon/cphalcon | <5.14.1 |
5.14.1 |
Affected products
- phalcon cphalcon
Classification
References
-
github.com
/phalcon/cphalcon/pull/17091
web
-
github.com
/phalcon/cphalcon/commit/ad53ab1b2e7ec59b3af92b0b37b8aaa099011137
web
-
github.com
/phalcon/cphalcon/security/advisories/GHSA-8jqh-95g6-7jpj
web
-
github.com
/phalcon/cphalcon/issues/17090
web
-
github.com
/phalcon/cphalcon/releases/tag/v5.14.1
web
-
nvd.nist.gov
/vuln/detail/CVE-2026-54736
advisory
-
github.com
/phalcon/cphalcon
package
Sources
- CVE List CVE-2026-54736
- GitHub Advisory GHSA-8jqh-95g6-7jpj
- NVD CVE-2026-54736
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