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CVE-2021-23841

MEDIUM · CVSS 5.9EPSS 7.4%EU EUVD

The OpenSSL public API function X509_issuer_and_serial_hash() attempts to create a unique hash value based on the issuer and serial number data contained within an X509 certificate. However it fails to correctly handle any errors that may occur while parsing the issuer field (which might occur if the issuer field is maliciously constructed). This may subsequently result in a NULL pointer deref and a crash leading to a potential denial of service attack. The function X509_issuer_and_serial_hash() is never directly called by OpenSSL itself so applications are only vulnerable if they use this function directly and they use it on certificates that may have been obtained from untrusted sources. OpenSSL versions 1.1.1i and below are affected by this issue. Users of these versions should upgrade to OpenSSL 1.1.1j. OpenSSL versions 1.0.2x and below are affected by this issue. However OpenSSL 1.0.2 is out of support and no longer receiving public updates. Premium support customers of OpenSSL 1.0.2 should upgrade to 1.0.2y. Other users should upgrade to 1.1.1j. Fixed in OpenSSL 1.1.1j (Affected 1.1.1-1.1.1i). Fixed in OpenSSL 1.0.2y (Affected 1.0.2-1.0.2x).

Key facts

CVSS score
5.9 (v3.1)
Severity
MEDIUM
CVSS vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
Weakness (CWE)
CWE-476
EPSS score
7.4% (94th percentile)
In CISA KEV
No
In EU EUVD
Yes (EUVD-2021-1630)
Published
February 16, 2021
NVD last modified
June 17, 2026
Status
Modified

EU Vulnerability Database (EUVD)

This vulnerability is also tracked by ENISA as EUVD-2021-1630 in the EU Vulnerability Database. Last updated in EUVD on September 16, 2024.

View on the EU Vulnerability Database

Affected products

  • apple / ipados
  • apple / iphone os
  • apple / macos
  • apple / safari
  • debian / debian linux
  • netapp / oncommand insight
  • netapp / oncommand workflow automation
  • netapp / snapcenter
  • openssl / openssl
  • oracle / business intelligence
  • oracle / business intelligence
  • oracle / business intelligence
  • oracle / business intelligence
  • oracle / communications cloud native core policy
  • oracle / enterprise manager for storage management
  • oracle / enterprise manager ops center
  • oracle / essbase
  • oracle / graalvm
  • oracle / graalvm
  • oracle / graalvm
  • oracle / jd edwards world security
  • oracle / mysql enterprise monitor
  • oracle / mysql server
  • oracle / peoplesoft enterprise peopletools
  • oracle / peoplesoft enterprise peopletools
  • oracle / peoplesoft enterprise peopletools
  • oracle / zfs storage appliance kit
  • siemens / sinec ins
  • siemens / sinec ins
  • siemens / sinec ins
  • tenable / nessus network monitor
  • tenable / nessus network monitor
  • tenable / nessus network monitor
  • tenable / nessus network monitor
  • tenable / nessus network monitor
  • tenable / tenable.sc

Certified products that may be affected

5 FIPS 140 or Common Criteria certified products, from automated matching by sec-certs.org.

References

Last updated September 17, 2026 · Source: NVD, CISA KEV, FIRST.org EPSS

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