CVE-2026-54736 (GCVE-0-2026-54736)

Vulnerability from cvelistv5 – Published: 2026-07-10 21:02 – Updated: 2026-07-10 21:02
VLAI
Title
Phalcon: Non-constant-time HMAC verification in `Encryption\Crypt::decrypt` (timing side-channel)
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.
Severity
8.2 (High)
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
CWE
  • CWE-208 - Observable Timing Discrepancy
  • CWE-347 - Improper Verification of Cryptographic Signature
Assigner
References
Impacted products
Vendor Product Version
phalcon cphalcon Affected: < 5.14.1
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  "containers": {
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      "affected": [
        {
          "product": "cphalcon",
          "vendor": "phalcon",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 5.14.1"
            }
          ]
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      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "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."
        }
      ],
      "metrics": [
        {
          "cvssV4_0": {
            "attackComplexity": "HIGH",
            "attackRequirements": "NONE",
            "attackVector": "NETWORK",
            "baseScore": 8.2,
            "baseSeverity": "HIGH",
            "privilegesRequired": "NONE",
            "subAvailabilityImpact": "NONE",
            "subConfidentialityImpact": "NONE",
            "subIntegrityImpact": "NONE",
            "userInteraction": "NONE",
            "vectorString": "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",
            "version": "4.0",
            "vulnAvailabilityImpact": "NONE",
            "vulnConfidentialityImpact": "NONE",
            "vulnIntegrityImpact": "HIGH"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-208",
              "description": "CWE-208: Observable Timing Discrepancy",
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              "type": "CWE"
            }
          ]
        },
        {
          "descriptions": [
            {
              "cweId": "CWE-347",
              "description": "CWE-347: Improper Verification of Cryptographic Signature",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-07-10T21:02:53.873Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/phalcon/cphalcon/security/advisories/GHSA-8jqh-95g6-7jpj",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/phalcon/cphalcon/security/advisories/GHSA-8jqh-95g6-7jpj"
        },
        {
          "name": "https://github.com/phalcon/cphalcon/issues/17090",
          "tags": [
            "x_refsource_MISC"
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          "url": "https://github.com/phalcon/cphalcon/issues/17090"
        },
        {
          "name": "https://github.com/phalcon/cphalcon/pull/17091",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/phalcon/cphalcon/pull/17091"
        },
        {
          "name": "https://github.com/phalcon/cphalcon/commit/ad53ab1b2e7ec59b3af92b0b37b8aaa099011137",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/phalcon/cphalcon/commit/ad53ab1b2e7ec59b3af92b0b37b8aaa099011137"
        },
        {
          "name": "https://github.com/phalcon/cphalcon/releases/tag/v5.14.1",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/phalcon/cphalcon/releases/tag/v5.14.1"
        }
      ],
      "source": {
        "advisory": "GHSA-8jqh-95g6-7jpj",
        "discovery": "UNKNOWN"
      },
      "title": "Phalcon: Non-constant-time HMAC verification in `Encryption\\Crypt::decrypt` (timing side-channel)"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-54736",
    "datePublished": "2026-07-10T21:02:53.873Z",
    "dateReserved": "2026-06-15T23:07:33.233Z",
    "dateUpdated": "2026-07-10T21:02:53.873Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-54736\",\"sourceIdentifier\":\"security-advisories@github.com\",\"published\":\"2026-07-10T22:16:42.970\",\"lastModified\":\"2026-07-10T22:16:42.970\",\"vulnStatus\":\"Received\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"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\":[{\"source\":\"security-advisories@github.com\",\"affectedData\":[{\"vendor\":\"phalcon\",\"product\":\"cphalcon\",\"versions\":[{\"version\":\"\u003c 5.14.1\",\"status\":\"affected\"}]}]}],\"metrics\":{\"cvssMetricV40\":[{\"source\":\"security-advisories@github.com\",\"type\":\"Secondary\",\"cvssData\":{\"version\":\"4.0\",\"vectorString\":\"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\",\"baseScore\":8.2,\"baseSeverity\":\"HIGH\",\"attackVector\":\"NETWORK\",\"attackComplexity\":\"HIGH\",\"attackRequirements\":\"NONE\",\"privilegesRequired\":\"NONE\",\"userInteraction\":\"NONE\",\"vulnConfidentialityImpact\":\"NONE\",\"vulnIntegrityImpact\":\"HIGH\",\"vulnAvailabilityImpact\":\"NONE\",\"subConfidentialityImpact\":\"NONE\",\"subIntegrityImpact\":\"NONE\",\"subAvailabilityImpact\":\"NONE\",\"exploitMaturity\":\"NOT_DEFINED\",\"confidentialityRequirement\":\"NOT_DEFINED\",\"integrityRequirement\":\"NOT_DEFINED\",\"availabilityRequirement\":\"NOT_DEFINED\",\"modifiedAttackVector\":\"NOT_DEFINED\",\"modifiedAttackComplexity\":\"NOT_DEFINED\",\"modifiedAttackRequirements\":\"NOT_DEFINED\",\"modifiedPrivilegesRequired\":\"NOT_DEFINED\",\"modifiedUserInteraction\":\"NOT_DEFINED\",\"modifiedVulnConfidentialityImpact\":\"NOT_DEFINED\",\"modifiedVulnIntegrityImpact\":\"NOT_DEFINED\",\"modifiedVulnAvailabilityImpact\":\"NOT_DEFINED\",\"modifiedSubConfidentialityImpact\":\"NOT_DEFINED\",\"modifiedSubIntegrityImpact\":\"NOT_DEFINED\",\"modifiedSubAvailabilityImpact\":\"NOT_DEFINED\",\"Safety\":\"NOT_DEFINED\",\"Automatable\":\"NOT_DEFINED\",\"Recovery\":\"NOT_DEFINED\",\"valueDensity\":\"NOT_DEFINED\",\"vulnerabilityResponseEffort\":\"NOT_DEFINED\",\"providerUrgency\":\"NOT_DEFINED\"}}]},\"weaknesses\":[{\"source\":\"security-advisories@github.com\",\"type\":\"Primary\",\"description\":[{\"lang\":\"en\",\"value\":\"CWE-208\"},{\"lang\":\"en\",\"value\":\"CWE-347\"}]}],\"references\":[{\"url\":\"https://github.com/phalcon/cphalcon/commit/ad53ab1b2e7ec59b3af92b0b37b8aaa099011137\",\"source\":\"security-advisories@github.com\"},{\"url\":\"https://github.com/phalcon/cphalcon/issues/17090\",\"source\":\"security-advisories@github.com\"},{\"url\":\"https://github.com/phalcon/cphalcon/pull/17091\",\"source\":\"security-advisories@github.com\"},{\"url\":\"https://github.com/phalcon/cphalcon/releases/tag/v5.14.1\",\"source\":\"security-advisories@github.com\"},{\"url\":\"https://github.com/phalcon/cphalcon/security/advisories/GHSA-8jqh-95g6-7jpj\",\"source\":\"security-advisories@github.com\"}]}}"
  }
}



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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

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  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
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  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


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