FKIE_CVE-2026-28388

Vulnerability from fkie_nvd - Published: 2026-04-07 22:16 - Updated: 2026-04-08 21:27
Severity ?
Summary
Issue summary: When a delta CRL that contains a Delta CRL Indicator extension is processed a NULL pointer dereference might happen if the required CRL Number extension is missing. Impact summary: A NULL pointer dereference can trigger a crash which leads to a Denial of Service for an application. When CRL processing and delta CRL processing is enabled during X.509 certificate verification, the delta CRL processing does not check whether the CRL Number extension is NULL before dereferencing it. When a malformed delta CRL file is being processed, this parameter can be NULL, causing a NULL pointer dereference. Exploiting this issue requires the X509_V_FLAG_USE_DELTAS flag to be enabled in the verification context, the certificate being verified to contain a freshestCRL extension or the base CRL to have the EXFLAG_FRESHEST flag set, and an attacker to provide a malformed CRL to an application that processes it. The vulnerability is limited to Denial of Service and cannot be escalated to achieve code execution or memory disclosure. For that reason the issue was assessed as Low severity according to our Security Policy. 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
openssl-security@openssl.orghttps://github.com/openssl/openssl/commit/59c3b3158553ab53275bbbccca5cb305d591cf2e
openssl-security@openssl.orghttps://github.com/openssl/openssl/commit/5a0b4930779cd2408880979db765db919da55139
openssl-security@openssl.orghttps://github.com/openssl/openssl/commit/602542f2c0c2d5edb47128f93eac10b62aeeefb3
openssl-security@openssl.orghttps://github.com/openssl/openssl/commit/a9d187dd1000130100fa7ab915f8513532cb3bb8
openssl-security@openssl.orghttps://github.com/openssl/openssl/commit/d3a901e8d9f021f3e67d6cfbc12e768129862726
openssl-security@openssl.orghttps://openssl-library.org/news/secadv/20260407.txt
Impacted products
Vendor Product Version
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{
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "Issue summary: When a delta CRL that contains a Delta CRL Indicator extension\nis processed a NULL pointer dereference might happen if the required CRL\nNumber extension is missing.\n\nImpact summary: A NULL pointer dereference can trigger a crash which\nleads to a Denial of Service for an application.\n\nWhen CRL processing and delta CRL processing is enabled during X.509\ncertificate verification, the delta CRL processing does not check\nwhether the CRL Number extension is NULL before dereferencing it.\nWhen a malformed delta CRL file is being processed, this parameter\ncan be NULL, causing a NULL pointer dereference.\n\nExploiting this issue requires the X509_V_FLAG_USE_DELTAS flag to be enabled in\nthe verification context, the certificate being verified to contain a\nfreshestCRL extension or the base CRL to have the EXFLAG_FRESHEST flag set, and\nan attacker to provide a malformed CRL to an application that processes it.\n\nThe vulnerability is limited to Denial of Service and cannot be escalated to\nachieve code execution or memory disclosure. For that reason the issue was\nassessed as Low severity according to our Security Policy.\n\nThe FIPS modules in 3.6, 3.5, 3.4, 3.3 and 3.0 are not affected by this issue,\nas the affected code is outside the OpenSSL FIPS module boundary."
    }
  ],
  "id": "CVE-2026-28388",
  "lastModified": "2026-04-08T21:27:00.663",
  "metrics": {},
  "published": "2026-04-07T22:16:20.863",
  "references": [
    {
      "source": "openssl-security@openssl.org",
      "url": "https://github.com/openssl/openssl/commit/59c3b3158553ab53275bbbccca5cb305d591cf2e"
    },
    {
      "source": "openssl-security@openssl.org",
      "url": "https://github.com/openssl/openssl/commit/5a0b4930779cd2408880979db765db919da55139"
    },
    {
      "source": "openssl-security@openssl.org",
      "url": "https://github.com/openssl/openssl/commit/602542f2c0c2d5edb47128f93eac10b62aeeefb3"
    },
    {
      "source": "openssl-security@openssl.org",
      "url": "https://github.com/openssl/openssl/commit/a9d187dd1000130100fa7ab915f8513532cb3bb8"
    },
    {
      "source": "openssl-security@openssl.org",
      "url": "https://github.com/openssl/openssl/commit/d3a901e8d9f021f3e67d6cfbc12e768129862726"
    },
    {
      "source": "openssl-security@openssl.org",
      "url": "https://openssl-library.org/news/secadv/20260407.txt"
    }
  ],
  "sourceIdentifier": "openssl-security@openssl.org",
  "vulnStatus": "Awaiting Analysis",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-476"
        }
      ],
      "source": "openssl-security@openssl.org",
      "type": "Secondary"
    }
  ]
}


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