CVE-2026-28388 (GCVE-0-2026-28388)

Vulnerability from cvelistv5 – Published: 2026-04-07 22:00 – Updated: 2026-05-12 12:08
VLAI
Title
NULL Pointer Dereference When Processing a Delta CRL
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.
Severity
No CVSS data available.
CWE
  • CWE-476 - NULL Pointer Dereference
Assigner
References
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)
Affected: 1.1.1 , < 1.1.1zg (custom)
Affected: 1.0.2 , < 1.0.2zp (custom)
Create a notification for this product.
Date Public
2026-04-07 14:00
Credits
Igor Morgenstern (Aisle Research) Igor Morgenstern (Aisle Research)
Show details on NVD website
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For that reason the issue was\u003cbr\u003eassessed as Low severity according to our Security Policy.\u003cbr\u003e\u003cbr\u003eThe FIPS modules in 3.6, 3.5, 3.4, 3.3 and 3.0 are not affected by this issue,\u003cbr\u003eas the affected code is outside the OpenSSL FIPS module boundary.\", \"base64\": false}]}], \"problemTypes\": [{\"descriptions\": [{\"lang\": \"en\", \"type\": \"CWE\", \"cweId\": \"CWE-476\", \"description\": \"CWE-476 NULL Pointer Dereference\"}]}], \"providerMetadata\": {\"orgId\": \"3a12439a-ef3a-4c79-92e6-6081a721f1e5\", \"shortName\": \"openssl\", \"dateUpdated\": \"2026-04-07T22:00:52.382Z\"}}}",
      "cveMetadata": "{\"cveId\": \"CVE-2026-28388\", \"state\": \"PUBLISHED\", \"dateUpdated\": \"2026-04-10T20:18:43.095Z\", \"dateReserved\": \"2026-02-27T13:45:02.161Z\", \"assignerOrgId\": \"3a12439a-ef3a-4c79-92e6-6081a721f1e5\", \"datePublished\": \"2026-04-07T22:00:52.382Z\", \"assignerShortName\": \"openssl\"}",
      "dataType": "CVE_RECORD",
      "dataVersion": "5.2"
    }
  }
}


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Taxonomy of the tags.




Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

Author Source Type Date Other

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.