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Buffer overflow in CRL number parsing in wolfSSL

Type: advisorySources: OSV

Two buffer overflow vulnerabilities existed in the wolfSSL CRL parser when parsing CRL numbers: a heap-based buffer overflow could occur when improperly storing the CRL number as a hexadecimal string, and a stack-based overflow for sufficiently sized CRL numbers. With appropriately crafted CRLs, either of these out of bound writes could be triggered. Note this only affects builds that specifically enable CRL support, and the user would need to load a CRL from an untrusted source.

Products
Not specified
Affected versions
Not specified
Fixed versions
Not specified
CVEs
CVE-2026-3548
Confirmed fixed CVEs
Not specified
Updated in this feed
5 Nov 2026, 06:00 UTC · Revision 1

Source evidence

Buffer overflow in CRL number parsing in wolfSSL

core-osv · Original source

Published 19 Mar 2026, 17:45 UTC

Two buffer overflow vulnerabilities existed in the wolfSSL CRL parser when parsing CRL numbers: a heap-based buffer overflow could occur when improperly storing the CRL number as a hexadecimal string, and a stack-based overflow for sufficiently sized CRL numbers. With appropriately crafted CRLs, either of these out of bound writes could be triggered. Note this only affects builds that specifically enable CRL support, and the user would need to load a CRL from an untrusted source.

osv:CVE-2026-3548
Complete source record
{
  "id": "22746f8ee05069e84d3d288f502ed956b03327a37d88d0f3890cf7859b4ef3da",
  "url": "https://osv.dev/vulnerability/CVE-2026-3548",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Buffer overflow in CRL number parsing in wolfSSL",
    "summary": "Two buffer overflow vulnerabilities existed in the wolfSSL CRL parser when parsing CRL numbers: a heap-based buffer overflow could occur when improperly storing the CRL number as a hexadecimal string, and a stack-based overflow for sufficiently sized CRL numbers. With appropriately crafted CRLs, either of these out of bound writes could be triggered. Note this only affects builds that specifically enable CRL support, and the user would need to load a CRL from an untrusted source.",
    "evidence": "osv:CVE-2026-3548",
    "products": [],
    "severity": "high",
    "structured": {
      "id": "CVE-2026-3548",
      "aliases": [
        "CVE-2026-3548"
      ],
      "metrics": [
        {
          "type": "CVSS_V4",
          "score": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/wolfssl/wolfssl",
              "type": "GIT",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "922d04b3568c6428a9fb905ddee3ef5a68db3108"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "range": [
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                        "introduced": "0"
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                      {
                        "fixed": "5.9.0"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StandardRange"
                  },
                  {
                    "cpe": "cpe:2.3:a:wolfssl:wolfssl:*:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "fixed": "5.9.0"
                      }
                    ],
                    "source": "CPE_RANGE"
                  }
                ]
              }
            }
          ],
          "versions": [
            "v5.8.4-stable",
            "wolfEntropy2d",
            "v5.8.2-stable",
            "wolfEntropy1",
            "v5.8.0-stable",
            "v5.7.6-stable",
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            "v4.2.0c",
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          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-3548.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:43.279637305Z",
      "provider": "osv",
      "references": [
        "https://github.com/wolfSSL/wolfssl/pull/9628/",
        "https://github.com/wolfSSL/wolfssl/pull/9873/",
        "https://www.wolfssl.com/download/",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/3xxx/CVE-2026-3548.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-3548",
        "https://github.com/wolfSSL/wolfssl"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-122",
          "CWE-787"
        ],
        "cna_assigner": "wolfSSL",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/3xxx/CVE-2026-3548.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-3548",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 510915,
  "published_at": "2026-03-19T17:45:16.717+00:00"
}