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CVE-2026-91855

Status: DeferredMedium (5.5)—

A security flaw has been discovered in Open5GS up to 2.7.7. Affected by this vulnerability is an unknown functionality of the file lib/pfcp/handler.c of the component PFCP Message Handler. Performing a manipulation results in denial of service. Remote exploitation of the attack is possible. The exploit has been released to the public and may be used for attacks. The patch is named 028e1dbb5e3271035ccee906ef417a97fc523f71. Applying a patch is the recommended action to fix this issue. CVE-2025-29339 describes a different assertion failure vulnerability in Open5GS UPF.

CVSS

Exploitation probability (EPSS)

EPSS (Exploit Prediction Scoring System, FIRST) estimates how likely a vulnerability is to be exploited in the wild within 30 days. It complements CVSS (impact) and CISA KEV (confirmed exploitation).

Affected technologies (1)

⚠ AI-inferred from the description — NVD hasn't analyzed this CVE yet, these aren't verified CPEs.

Open5gs — Open5gsAI

CWEs

References

Raw JSON (NVD)

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{
  "id": "CVE-2026-91855",
  "cveTags": [],
  "metrics": {
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-91855",
          "role": "CISA Coordinator",
          "options": [
            {
              "exploitation": "poc"
            },
            {
              "automatable": "yes"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "version": "2.0.3",
          "timestamp": "2026-09-15T17:44:31.315009Z"
        }
      }
    ],
    "cvssMetricV2": [
      {
        "type": "Secondary",
        "source": "cna@vuldb.com",
        "cvssData": {
          "version": "2.0",
          "baseScore": 5,
          "accessVector": "NETWORK",
          "vectorString": "AV:N/AC:L/Au:N/C:N/I:N/A:P",
          "authentication": "NONE",
          "integrityImpact": "NONE",
          "accessComplexity": "LOW",
          "availabilityImpact": "PARTIAL",
          "confidentialityImpact": "NONE"
        },
        "acInsufInfo": false,
        "impactScore": 2.9,
        "baseSeverity": "MEDIUM",
        "obtainAllPrivilege": false,
        "exploitabilityScore": 10,
        "obtainUserPrivilege": false,
        "obtainOtherPrivilege": false,
        "userInteractionRequired": false
      }
    ],
    "cvssMetricV31": [
      {
        "type": "Secondary",
        "source": "cna@vuldb.com",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 5.3,
          "attackVector": "NETWORK",
          "baseSeverity": "MEDIUM",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L",
          "integrityImpact": "NONE",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "LOW",
          "privilegesRequired": "NONE",
          "confidentialityImpact": "NONE"
        },
        "impactScore": 1.4,
        "exploitabilityScore": 3.9
      }
    ],
    "cvssMetricV40": [
      {
        "type": "Secondary",
        "source": "cna@vuldb.com",
        "cvssData": {
          "Safety": "NOT_DEFINED",
          "version": "4.0",
          "Recovery": "NOT_DEFINED",
          "baseScore": 5.5,
          "Automatable": "NOT_DEFINED",
          "attackVector": "NETWORK",
          "baseSeverity": "MEDIUM",
          "valueDensity": "NOT_DEFINED",
          "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:P/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",
          "exploitMaturity": "PROOF_OF_CONCEPT",
          "providerUrgency": "NOT_DEFINED",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "attackRequirements": "NONE",
          "privilegesRequired": "NONE",
          "subIntegrityImpact": "NONE",
          "vulnIntegrityImpact": "NONE",
          "integrityRequirement": "NOT_DEFINED",
          "modifiedAttackVector": "NOT_DEFINED",
          "subAvailabilityImpact": "NONE",
          "vulnAvailabilityImpact": "LOW",
          "availabilityRequirement": "NOT_DEFINED",
          "modifiedUserInteraction": "NOT_DEFINED",
          "modifiedAttackComplexity": "NOT_DEFINED",
          "subConfidentialityImpact": "NONE",
          "vulnConfidentialityImpact": "NONE",
          "confidentialityRequirement": "NOT_DEFINED",
          "modifiedAttackRequirements": "NOT_DEFINED",
          "modifiedPrivilegesRequired": "NOT_DEFINED",
          "modifiedSubIntegrityImpact": "NOT_DEFINED",
          "modifiedVulnIntegrityImpact": "NOT_DEFINED",
          "vulnerabilityResponseEffort": "NOT_DEFINED",
          "modifiedSubAvailabilityImpact": "NOT_DEFINED",
          "modifiedVulnAvailabilityImpact": "NOT_DEFINED",
          "modifiedSubConfidentialityImpact": "NOT_DEFINED",
          "modifiedVulnConfidentialityImpact": "NOT_DEFINED"
        }
      }
    ]
  },
  "affected": [
    {
      "source": "cna@vuldb.com",
      "affectedData": [
        {
          "cpes": [
            "cpe:2.3:a:open5gs:open5gs:*:*:*:*:*:*:*:*"
          ],
          "vendor": "n/a",
          "modules": [
            "PFCP Message Handler"
          ],
          "product": "Open5GS",
          "versions": [
            {
              "status": "affected",
              "version": "2.7.0"
            },
            {
              "status": "affected",
              "version": "2.7.1"
            },
            {
              "status": "affected",
              "version": "2.7.2"
            },
            {
              "status": "affected",
              "version": "2.7.3"
            },
            {
              "status": "affected",
              "version": "2.7.4"
            },
            {
              "status": "affected",
              "version": "2.7.5"
            },
            {
              "status": "affected",
              "version": "2.7.6"
            },
            {
              "status": "affected",
              "version": "2.7.7"
            }
          ]
        }
      ]
    }
  ],
  "published": "2026-09-15T17:17:39.867",
  "references": [
    {
      "url": "https://github.com/open5gs/open5gs/",
      "source": "cna@vuldb.com"
    },
    {
      "url": "https://github.com/open5gs/open5gs/commit/028e1dbb5e3271035ccee906ef417a97fc523f71",
      "source": "cna@vuldb.com"
    },
    {
      "url": "https://github.com/open5gs/open5gs/issues/4699",
      "source": "cna@vuldb.com"
    },
    {
      "url": "https://vuldb.com/cve/CVE-2026-91855",
      "source": "cna@vuldb.com"
    },
    {
      "url": "https://vuldb.com/submit/933834",
      "source": "cna@vuldb.com"
    },
    {
      "url": "https://vuldb.com/vuln/404086",
      "source": "cna@vuldb.com"
    },
    {
      "url": "https://vuldb.com/vuln/404086/cti",
      "source": "cna@vuldb.com"
    }
  ],
  "vulnStatus": "Deferred",
  "weaknesses": [
    {
      "type": "Secondary",
      "source": "cna@vuldb.com",
      "description": [
        {
          "lang": "en",
          "value": "CWE-404"
        }
      ]
    }
  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "A security flaw has been discovered in Open5GS up to 2.7.7. Affected by this vulnerability is an unknown functionality of the file lib/pfcp/handler.c of the component PFCP Message Handler. Performing a manipulation results in denial of service. Remote exploitation of the attack is possible. The exploit has been released to the public and may be used for attacks. The patch is named 028e1dbb5e3271035ccee906ef417a97fc523f71. Applying a patch is the recommended action to fix this issue. CVE-2025-29339 describes a different assertion failure vulnerability in Open5GS UPF."
    }
  ],
  "lastModified": "2026-09-16T13:42:49.240",
  "sourceIdentifier": "cna@vuldb.com"
}