Vulnerability-Lookup

FKIE_CVE-2026-31789

Vulnerability from fkie_nvd - Published: 2026-04-07 22:16 - Updated: 2026-04-23 15:39

Severity ?

9.8 (Critical) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Summary

Issue summary: Converting an excessively large OCTET STRING value to a hexadecimal string leads to a heap buffer overflow on 32 bit platforms. Impact summary: A heap buffer overflow may lead to a crash or possibly an attacker controlled code execution or other undefined behavior. If an attacker can supply a crafted X.509 certificate with an excessively large OCTET STRING value in extensions such as the Subject Key Identifier (SKID) or Authority Key Identifier (AKID) which are being converted to hex, the size of the buffer needed for the result is calculated as multiplication of the input length by 3. On 32 bit platforms, this multiplication may overflow resulting in the allocation of a smaller buffer and a heap buffer overflow. Applications and services that print or log contents of untrusted X.509 certificates are vulnerable to this issue. As the certificates would have to have sizes of over 1 Gigabyte, printing or logging such certificates is a fairly unlikely operation and only 32 bit platforms are affected, this issue was assigned Low severity. The FIPS modules in 3.6, 3.5, 3.4, 3.3 and 3.0 are not affected by this issue, as the affected code is outside the OpenSSL FIPS module boundary.

References

URL	Tags
openssl-security@openssl.org	https://github.com/openssl/openssl/commit/364f095b80601db632b0def6a33316967f863bde	Patch
openssl-security@openssl.org	https://github.com/openssl/openssl/commit/7a9087efd769f362ad9c0e30c7baaa6bbfa65ecf	Patch
openssl-security@openssl.org	https://github.com/openssl/openssl/commit/945b935ac66cc7f1a41f1b849c7c25adb5351f49	Patch
openssl-security@openssl.org	https://github.com/openssl/openssl/commit/a24216018e1ede8ff01a4ff5afff7dfbd443e2f9	Patch
openssl-security@openssl.org	https://github.com/openssl/openssl/commit/a91e537d16d74050dbde50bb0dfb1fe9930f0521	Patch
openssl-security@openssl.org	https://openssl-library.org/news/secadv/20260407.txt	Vendor Advisory

Impacted products

Vendor	Product	Version
openssl	openssl	*
openssl	openssl	*
openssl	openssl	*
openssl	openssl	*
openssl	openssl	*

JSON

To clipboard

{
  "configurations": [
    {
      "nodes": [
        {
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:a:openssl:openssl:*:*:*:*:*:*:*:*",
              "matchCriteriaId": "B28A8143-89A4-4332-A1F8-A65FB5AA829F",
              "versionEndExcluding": "3.0.20",
              "versionStartIncluding": "3.0.0",
              "vulnerable": true
            },
            {
              "criteria": "cpe:2.3:a:openssl:openssl:*:*:*:*:*:*:*:*",
              "matchCriteriaId": "CF303B21-D9BF-461D-B7B0-A3FE1D557A9F",
              "versionEndExcluding": "3.3.7",
              "versionStartIncluding": "3.3.0",
              "vulnerable": true
            },
            {
              "criteria": "cpe:2.3:a:openssl:openssl:*:*:*:*:*:*:*:*",
              "matchCriteriaId": "DCCE43D0-8F17-475D-9EE6-842F758A9905",
              "versionEndExcluding": "3.4.5",
              "versionStartIncluding": "3.4.0",
              "vulnerable": true
            },
            {
              "criteria": "cpe:2.3:a:openssl:openssl:*:*:*:*:*:*:*:*",
              "matchCriteriaId": "F6BC0271-444D-4597-BF05-DC60034EAA49",
              "versionEndExcluding": "3.5.6",
              "versionStartIncluding": "3.5.0",
              "vulnerable": true
            },
            {
              "criteria": "cpe:2.3:a:openssl:openssl:*:*:*:*:*:*:*:*",
              "matchCriteriaId": "4A9E621D-29D8-418A-BF37-BED333C14507",
              "versionEndExcluding": "3.6.2",
              "versionStartIncluding": "3.6.0",
              "vulnerable": true
            }
          ],
          "negate": false,
          "operator": "OR"
        }
      ]
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "Issue summary: Converting an excessively large OCTET STRING value to\na hexadecimal string leads to a heap buffer overflow on 32 bit platforms.\n\nImpact summary: A heap buffer overflow may lead to a crash or possibly\nan attacker controlled code execution or other undefined behavior.\n\nIf an attacker can supply a crafted X.509 certificate with an excessively\nlarge OCTET STRING value in extensions such as the Subject Key Identifier\n(SKID) or Authority Key Identifier (AKID) which are being converted to hex,\nthe size of the buffer needed for the result is calculated as multiplication\nof the input length by 3. On 32 bit platforms, this multiplication may overflow\nresulting in the allocation of a smaller buffer and a heap buffer overflow.\n\nApplications and services that print or log contents of untrusted X.509\ncertificates are vulnerable to this issue. As the certificates would have\nto have sizes of over 1 Gigabyte, printing or logging such certificates\nis a fairly unlikely operation and only 32 bit platforms are affected,\nthis issue was assigned Low severity.\n\nThe FIPS modules in 3.6, 3.5, 3.4, 3.3 and 3.0 are not affected by this\nissue, as the affected code is outside the OpenSSL FIPS module boundary."
    }
  ],
  "id": "CVE-2026-31789",
  "lastModified": "2026-04-23T15:39:34.377",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "HIGH",
          "baseScore": 9.8,
          "baseSeverity": "CRITICAL",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 3.9,
        "impactScore": 5.9,
        "source": "nvd@nist.gov",
        "type": "Primary"
      }
    ]
  },
  "published": "2026-04-07T22:16:21.617",
  "references": [
    {
      "source": "openssl-security@openssl.org",
      "tags": [
        "Patch"
      ],
      "url": "https://github.com/openssl/openssl/commit/364f095b80601db632b0def6a33316967f863bde"
    },
    {
      "source": "openssl-security@openssl.org",
      "tags": [
        "Patch"
      ],
      "url": "https://github.com/openssl/openssl/commit/7a9087efd769f362ad9c0e30c7baaa6bbfa65ecf"
    },
    {
      "source": "openssl-security@openssl.org",
      "tags": [
        "Patch"
      ],
      "url": "https://github.com/openssl/openssl/commit/945b935ac66cc7f1a41f1b849c7c25adb5351f49"
    },
    {
      "source": "openssl-security@openssl.org",
      "tags": [
        "Patch"
      ],
      "url": "https://github.com/openssl/openssl/commit/a24216018e1ede8ff01a4ff5afff7dfbd443e2f9"
    },
    {
      "source": "openssl-security@openssl.org",
      "tags": [
        "Patch"
      ],
      "url": "https://github.com/openssl/openssl/commit/a91e537d16d74050dbde50bb0dfb1fe9930f0521"
    },
    {
      "source": "openssl-security@openssl.org",
      "tags": [
        "Vendor Advisory"
      ],
      "url": "https://openssl-library.org/news/secadv/20260407.txt"
    }
  ],
  "sourceIdentifier": "openssl-security@openssl.org",
  "vulnStatus": "Analyzed",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-787"
        }
      ],
      "source": "openssl-security@openssl.org",
      "type": "Secondary"
    }
  ]
}

CVE-2026-31789 (GCVE-0-2026-31789)

Vulnerability from cvelistv5 – Published: 2026-04-07 22:00 – Updated: 2026-04-13 13:04

Title

Heap Buffer Overflow in Hexadecimal Conversion

Summary

Severity ?

No CVSS data available.

CWE

CWE-787 - Out-of-bounds Write

Assigner

openssl

References

URL

Tags

	https://openssl-library.org/news/secadv/20260407.txt	vendor-advisory
	https://github.com/openssl/openssl/commit/a242160…	patch
	https://github.com/openssl/openssl/commit/945b935…	patch
	https://github.com/openssl/openssl/commit/364f095…	patch
	https://github.com/openssl/openssl/commit/7a9087e…	patch
	https://github.com/openssl/openssl/commit/a91e537…	patch

Impacted products

	Vendor	Product	Version
	OpenSSL	OpenSSL	Affected: 3.6.0 , < 3.6.2 (semver) Affected: 3.5.0 , < 3.5.6 (semver) Affected: 3.4.0 , < 3.4.5 (semver) Affected: 3.3.0 , < 3.3.7 (semver) Affected: 3.0.0 , < 3.0.20 (semver)

Date Public ?

2026-04-07 14:00

Credits

Quoc Tran (Xint.io - US Team) Igor Ustinov

Show details on NVD website

JSON

To clipboard

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        "metrics": [
          {
            "other": {
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                "id": "CVE-2026-31789",
                "options": [
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                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "total"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-04-09T03:56:05.246752Z",
                "version": "2.0.3"
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        ],
        "providerMetadata": {
          "dateUpdated": "2026-04-13T13:04:17.163Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
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    "cna": {
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              "status": "affected",
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            },
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              "status": "affected",
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            },
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              "lessThan": "3.4.5",
              "status": "affected",
              "version": "3.4.0",
              "versionType": "semver"
            },
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              "lessThan": "3.3.7",
              "status": "affected",
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        }
      ],
      "datePublic": "2026-04-07T14:00:00.000Z",
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}

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

FKIE_CVE-2026-31789

CVE-2026-31789 (GCVE-0-2026-31789)

Tags

Sightings

Nomenclature