How severe is CVE-2026-54736?

CVE-2026-54736 has a CVSS 4.0 base score of 8.2, rated high severity.

Is CVE-2026-54736 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (4th percentile), an estimate of the probability of exploitation in the next 30 days.

How do I fix CVE-2026-54736?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2026-54736 published?

CVE-2026-54736 was published on 2026-07-10 and last updated on 2026-07-13.

CVE-2026-54736

CVE-2026-54736 is a high-severity vulnerability with a CVSS 4.0 base score of 8.2. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-208.

Key facts

Severity: High (CVSS 4.0 base score 8.2)
EPSS exploit prediction: 0% (4th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-208
Published: 2026-07-10
Last modified: 2026-07-13

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.

Frequently asked questions

What is CVE-2026-54736?: 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.
How severe is CVE-2026-54736?: CVE-2026-54736 has a CVSS 4.0 base score of 8.2, rated high severity.
Is CVE-2026-54736 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (4th percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2026-54736?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2026-54736 published?: CVE-2026-54736 was published on 2026-07-10 and last updated on 2026-07-13.

References

Other CWE-208 vulnerabilities

CVE-2023-41313 — Critical (CVSS 9.8): The authentication method in Apache Doris versions before 2.0.0 was vulnerable to timing attacks. Users are recommended…
CVE-2026-16315 — High (CVSS 8.7): OMICRON StationGuard before version 4.10 contains a cryptographic timing side-channel vulnerability in the backend…
CVE-2024-42512 — High (CVSS 8.6): Vulnerability in the OPC UA .NET Standard Stack before 1.5.374.158 allows an unauthorized attacker to bypass…
CVE-2026-43606 — High (CVSS 8.5): Observable Timing Discrepancy in the AMD Vitis Libraries ECDSA secp256k1 component could allow attackers with local…
CVE-2025-53940 — High (CVSS 8.5): Quiet is an alternative to team chat apps like Slack, Discord, and Element that does not require trusting a central…
CVE-2026-16731 — High (CVSS 8.3): OMICRON StationScout before version 3.05 contains a cryptographic timing side-channel vulnerability in the backend…

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