{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-54411",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-06-15T16:59:25.401303Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-06-15T16:59:37.818Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "collectionURL": "https://github.com/linux-pam/linux-pam",
          "defaultStatus": "unknown",
          "modules": [
            "pam_userdb"
          ],
          "product": "Linux-PAM",
          "programFiles": [
            "modules/pam_userdb/pam_userdb.c"
          ],
          "repo": "https://github.com/linux-pam/linux-pam",
          "vendor": "Linux-PAM",
          "versions": [
            {
              "lessThanOrEqual": "1.7.2",
              "status": "affected",
              "version": "0",
              "versionType": "semver"
            }
          ]
        }
      ],
      "credits": [
        {
          "lang": "en",
          "type": "finder",
          "value": "Xurshidbek Sobirjonov"
        }
      ],
      "datePublic": "2026-06-14T17:21:43.853Z",
      "descriptions": [
        {
          "lang": "en",
          "supportingMedia": [
            {
              "base64": false,
              "type": "text/html",
              "value": "\u003cp\u003eLinux-PAM through 1.7.2 contains an observable timing discrepancy (CWE-208) in the pam_userdb module\u0027s plaintext-password comparison path in modules/pam_userdb/pam_userdb.c that allows a local or network-adjacent attacker able to repeatedly drive authentication through a calling service to recover the plaintext password of a target account by measuring response-timing differences.\u003c/p\u003e"
            }
          ],
          "value": "Linux-PAM through 1.7.2 contains an observable timing discrepancy (CWE-208) in the pam_userdb module\u0027s plaintext-password comparison path in modules/pam_userdb/pam_userdb.c that allows a local or network-adjacent attacker able to repeatedly drive authentication through a calling service to recover the plaintext password of a target account by measuring response-timing differences."
        }
      ],
      "impacts": [
        {
          "descriptions": [
            {
              "lang": "en",
              "value": "An attacker who can repeatedly drive authentication through a service that invokes pam_userdb with plaintext-password configuration and without an artificial failure delay can measure response-timing differences to learn the correct password length and recover the plaintext password byte by byte. Recovery requires many measurements per character and is sensitive to scheduling and network jitter; recovery of one user\u0027s secret does not by itself yield access to other accounts. Practical exploitation is gated by an administrative misconfiguration (pam_userdb storing passwords in plaintext, reached when the module is configured with crypt=none, with an unknown crypt method, or with no crypt= option) and by the absence of failure-delay or rate-limiting in the calling service."
            }
          ]
        }
      ],
      "metrics": [
        {
          "cvssV4_0": {
            "Automatable": "NO",
            "Recovery": "NOT_DEFINED",
            "Safety": "NOT_DEFINED",
            "attackComplexity": "HIGH",
            "attackRequirements": "PRESENT",
            "attackVector": "NETWORK",
            "baseScore": 6.9,
            "baseSeverity": "MEDIUM",
            "exploitMaturity": "PROOF_OF_CONCEPT",
            "privilegesRequired": "NONE",
            "providerUrgency": "NOT_DEFINED",
            "subAvailabilityImpact": "NONE",
            "subConfidentialityImpact": "NONE",
            "subIntegrityImpact": "NONE",
            "userInteraction": "NONE",
            "valueDensity": "DIFFUSE",
            "vectorString": "CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:P/AU:N/V:D",
            "version": "4.0",
            "vulnAvailabilityImpact": "NONE",
            "vulnConfidentialityImpact": "HIGH",
            "vulnIntegrityImpact": "NONE",
            "vulnerabilityResponseEffort": "NOT_DEFINED"
          },
          "format": "CVSS",
          "scenarios": [
            {
              "lang": "en",
              "value": "An attacker repeatedly authenticates through a service that calls pam_userdb (plaintext mode) and measures the time the service takes to reject each candidate password to learn the password length and recover the password one byte at a time."
            }
          ]
        },
        {
          "cvssV3_1": {
            "attackComplexity": "HIGH",
            "attackVector": "NETWORK",
            "availabilityImpact": "NONE",
            "baseScore": 5.9,
            "baseSeverity": "MEDIUM",
            "confidentialityImpact": "HIGH",
            "integrityImpact": "NONE",
            "privilegesRequired": "NONE",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N",
            "version": "3.1"
          },
          "format": "CVSS",
          "scenarios": [
            {
              "lang": "en",
              "value": "GENERAL"
            }
          ]
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-208",
              "description": "CWE-208 Observable Timing Discrepancy",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-10T11:43:56.355Z",
        "orgId": "309f9ea4-e3e9-4c6c-b79d-e8eb01244f2c",
        "shortName": "TuranSec"
      },
      "references": [
        {
          "name": "Linux-PAM - upstream repository",
          "tags": [
            "product"
          ],
          "url": "https://github.com/linux-pam/linux-pam"
        },
        {
          "name": "Vulnerable plaintext-password comparison in pam_userdb.c (master)",
          "tags": [
            "product"
          ],
          "url": "https://github.com/linux-pam/linux-pam/blob/master/modules/pam_userdb/pam_userdb.c#L327"
        },
        {
          "name": "pam_consttime_streq helper available for the remediation",
          "tags": [
            "product"
          ],
          "url": "https://github.com/linux-pam/linux-pam/blob/master/libpam/include/pam_inline.h"
        },
        {
          "name": "CWE-208: Observable Timing Discrepancy",
          "tags": [
            "technical-description"
          ],
          "url": "https://cwe.mitre.org/data/definitions/208.html"
        }
      ],
      "source": {
        "discovery": "EXTERNAL"
      },
      "title": "Linux-PAM pam_userdb Observable Timing Discrepancy in Plaintext Password Comparison",
      "x_assigner_notes": "The vulnerable comparison was verified by direct source inspection of modules/pam_userdb/pam_userdb.c at tag v1.7.2 and at master HEAD as of disclosure: lines 327-332 perform a length-equality early exit followed by strncmp() / strncasecmp(). Linux-PAM has previously addressed the same weakness class in a sibling module: NEWS for Release 1.7.0 records \"pam_unix: compare password hashes in constant time\", and Release 1.6.0 hardened pam_mkhomedir \"against timing attacks\". The pam_consttime_streq() helper used by those fixes lives in libpam/include/pam_inline.h, which pam_userdb.c already includes, so the remediation in pam_userdb is a drop-in replacement of the strncmp call. The v1.7.2 release notes do not list a pam_userdb hardening change. Exploitation is gated by (a) the administrator having configured pam_userdb with plaintext password storage (crypt=none, unknown crypt method, or no crypt= option), a discouraged but documented configuration; and (b) the calling service not applying an authentication-failure delay - both gates raise attack complexity and bound real-world impact, so CVSS is scored MEDIUM rather than HIGH consistent with prior CWE-208 timing-leak CVE scoring.",
      "x_author": "Xurshidbek Sobirjonov"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "309f9ea4-e3e9-4c6c-b79d-e8eb01244f2c",
    "assignerShortName": "TuranSec",
    "cveId": "CVE-2026-54411",
    "datePublished": "2026-06-14T17:21:43.853Z",
    "dateReserved": "2026-06-13T16:39:46.122Z",
    "dateUpdated": "2026-08-10T11:43:56.355Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}