Vulnerability-Lookup

GHSA-5PWR-322W-8JR4

Vulnerability from github – Published: 2026-03-16 16:22 – Updated: 2026-03-19 18:28

Summary

pyOpenSSL DTLS cookie callback buffer overflow

Details

If a user provided callback to set_cookie_generate_callback returned a cookie value greater than 256 bytes, pyOpenSSL would overflow an OpenSSL provided buffer.

Cookie values that are too long are now rejected.

Severity ?

7.2 (High)


                  
                    CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U

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{
  "affected": [
    {
      "package": {
        "ecosystem": "PyPI",
        "name": "pyopenssl"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "22.0.0"
            },
            {
              "fixed": "26.0.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-27459"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-120"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-03-16T16:22:29Z",
    "nvd_published_at": "2026-03-18T00:16:19Z",
    "severity": "HIGH"
  },
  "details": "If a user provided callback to `set_cookie_generate_callback` returned a cookie value greater than 256 bytes, pyOpenSSL would overflow an OpenSSL provided buffer.\n\nCookie values that are too long are now rejected.",
  "id": "GHSA-5pwr-322w-8jr4",
  "modified": "2026-03-19T18:28:11Z",
  "published": "2026-03-16T16:22:29Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/pyca/pyopenssl/security/advisories/GHSA-5pwr-322w-8jr4"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-27459"
    },
    {
      "type": "WEB",
      "url": "https://github.com/pyca/pyopenssl/commit/57f09bb4bb051d3bc2a1abd36e9525313d5cd408"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/pyca/pyopenssl"
    },
    {
      "type": "WEB",
      "url": "https://github.com/pyca/pyopenssl/blob/358cbf29c4e364c59930e53a270116249581eaa3/CHANGELOG.rst"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U",
      "type": "CVSS_V4"
    }
  ],
  "summary": "pyOpenSSL DTLS cookie callback buffer overflow"
}

CVE-2026-27459 (GCVE-0-2026-27459)

Vulnerability from cvelistv5 – Published: 2026-03-17 23:34 – Updated: 2026-03-18 19:52

Title

pyOpenSSL DTLS cookie callback buffer overflow

Summary

pyOpenSSL is a Python wrapper around the OpenSSL library. Starting in version 22.0.0 and prior to version 26.0.0, if a user provided callback to `set_cookie_generate_callback` returned a cookie value greater than 256 bytes, pyOpenSSL would overflow an OpenSSL provided buffer. Starting in version 26.0.0, cookie values that are too long are now rejected.

Severity ?

7.2 (High)


                        
                          CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U

CWE

CWE-120 - Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')

Assigner

GitHub_M

References

URL

Tags

	https://github.com/pyca/pyopenssl/security/adviso…	x_refsource_CONFIRM
	https://github.com/pyca/pyopenssl/commit/57f09bb4…	x_refsource_MISC
	https://github.com/pyca/pyopenssl/blob/358cbf29c4…	x_refsource_MISC

Impacted products

	Vendor	Product	Version
	pyca	pyopenssl	Affected: >= 22.0.0, < 26.0.0

Show details on NVD website

JSON

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{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-27459",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "total"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-03-18T19:52:08.536876Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-03-18T19:52:15.812Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "pyopenssl",
          "vendor": "pyca",
          "versions": [
            {
              "status": "affected",
              "version": "\u003e= 22.0.0, \u003c 26.0.0"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "pyOpenSSL is a Python wrapper around the OpenSSL library. Starting in version 22.0.0 and prior to version 26.0.0, if a user provided callback to `set_cookie_generate_callback` returned a cookie value greater than 256 bytes, pyOpenSSL would overflow an OpenSSL provided buffer. Starting in version 26.0.0, cookie values that are too long are now rejected."
        }
      ],
      "metrics": [
        {
          "cvssV4_0": {
            "attackComplexity": "HIGH",
            "attackRequirements": "PRESENT",
            "attackVector": "NETWORK",
            "baseScore": 7.2,
            "baseSeverity": "HIGH",
            "privilegesRequired": "NONE",
            "subAvailabilityImpact": "NONE",
            "subConfidentialityImpact": "NONE",
            "subIntegrityImpact": "NONE",
            "userInteraction": "NONE",
            "vectorString": "CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U",
            "version": "4.0",
            "vulnAvailabilityImpact": "HIGH",
            "vulnConfidentialityImpact": "HIGH",
            "vulnIntegrityImpact": "HIGH"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-120",
              "description": "CWE-120: Buffer Copy without Checking Size of Input (\u0027Classic Buffer Overflow\u0027)",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-03-17T23:34:28.483Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/pyca/pyopenssl/security/advisories/GHSA-5pwr-322w-8jr4",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/pyca/pyopenssl/security/advisories/GHSA-5pwr-322w-8jr4"
        },
        {
          "name": "https://github.com/pyca/pyopenssl/commit/57f09bb4bb051d3bc2a1abd36e9525313d5cd408",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/pyca/pyopenssl/commit/57f09bb4bb051d3bc2a1abd36e9525313d5cd408"
        },
        {
          "name": "https://github.com/pyca/pyopenssl/blob/358cbf29c4e364c59930e53a270116249581eaa3/CHANGELOG.rst",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/pyca/pyopenssl/blob/358cbf29c4e364c59930e53a270116249581eaa3/CHANGELOG.rst"
        }
      ],
      "source": {
        "advisory": "GHSA-5pwr-322w-8jr4",
        "discovery": "UNKNOWN"
      },
      "title": "pyOpenSSL DTLS cookie callback buffer overflow"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-27459",
    "datePublished": "2026-03-17T23:34:28.483Z",
    "dateReserved": "2026-02-19T17:25:31.100Z",
    "dateUpdated": "2026-03-18T19:52:15.812Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date

Nomenclature

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.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

Action not permitted

GHSA-5PWR-322W-8JR4

CVE-2026-27459 (GCVE-0-2026-27459)

Tags

Sightings

Nomenclature