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Fencer Vulns
medium 5.9

CVE-2021-23841 json

Null pointer deref in X509_issuer_and_serial_hash()

published 2021-02-16 5 y ago modified 2026-07-25 3 mo ago also EUVD-2021-1630 , GHSA-84rm-qf37-fgc2 , JLSEC-2026-222 , RUSTSEC-2021-0058

cvss
5.9
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
7.4%
EPSS 7.4% chance of exploitation in 30 days, percentile 94%
public exploits
0
none known

Summary

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).

Patch / fix

  • crates.io openssl-src 111.14.0
  • julia OpenSSL_jll 1.1.10+0
  • julia Openresty_jll 1.19.9+0
  • openssl openssl 1.0.2y, 1.1.1j
  • apple safari 14.1.1
  • oracle mysql_enterprise_monitor 8.0.23
  • oracle mysql_server 5.7.33, 8.0.23
  • siemens sinec_ins 1.0
  • apple ipados 14.6
  • apple iphone_os 14.6
  • apple macos 11.4
  • openssl Debian 14, Debian 13, Debian 12 1.1.1j-1

debian advisories DEBIAN-CVE-2021-23841

  • openssl Ubuntu 16.04 LTS 1.0.2g-1ubuntu4.19
  • openssl Ubuntu 18.04 LTS 1.1.1-1ubuntu2.1~18.04.8
  • openssl Ubuntu 20.04 LTS 1.1.1f-1ubuntu2.2
  • openssl1.0 Ubuntu 18.04 LTS 1.0.2n-1ubuntu5.6
  • openssl Ubuntu Pro 14.04 LTS 1.0.1f-1ubuntu2.27+esm2

ubuntu advisories UBUNTU-CVE-2021-23841

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • jws5-tomcat jboss enterprise web server 5.6 9.0.50-3.redhat_00004.1.el7jws
  • jws5-tomcat jboss enterprise web server 5.6 9.0.50-3.redhat_00004.1.el8jws
  • jws5-tomcat-lib jboss enterprise web server 5.6 9.0.50-3.redhat_00004.1.el7jws
  • jws5-tomcat-lib jboss enterprise web server 5.6 9.0.50-3.redhat_00004.1.el8jws
  • jws5-tomcat-vault jboss enterprise web server 5.6 1.1.8-4.Final_redhat_00004.1.el7jws
  • jws5-tomcat-vault jboss enterprise web server 5.6 1.1.8-4.Final_redhat_00004.1.el8jws
  • jws5-tomcat-native jboss enterprise web server 5.6 1.2.30-3.redhat_3.el7jws
  • jws5-tomcat-native jboss enterprise web server 5.6 1.2.30-3.redhat_3.el8jws

red hat advisories RHSA-2021:4861RHSA-2021:4614RHSA-2021:4198RHSA-2021:4424RHSA-2021:3798

  • openssl SLES for SAP 12 SP3, SLES for SAP 12 SP2, SLES 12 SP3-LTSS +7 more 1.0.2j-60.66.1
  • openssl SLES 11 SP4-LTSS, SLE Point of Sale 11 SP3 0.9.8j-0.106.37.1
  • openssl1 SLES 11-SECURITY 1.0.1g-0.58.33.1
  • compat-openssl098 SLES for SAP 12 SP5, SLES for SAP 12 SP4, SLES for SAP 12 SP3 +2 more 0.9.8j-106.24.1
  • openssl-1_0_0 SLES for SAP 15 SP1, SLES for SAP 15, SLES 15-LTSS +7 more 1.0.2p-3.37.1
  • openssl-1_1 SLES for SAP 15, SLES 15-LTSS, SLE High Performance Computing 15-LTSS +1 more 1.1.0i-4.57.1
  • openssl-1_1 SLE Module for Basesystem 15 SP2, SLE Micro 5.0 1.1.1d-11.17.1
  • openssl-1_1 SLES for SAP 15 SP1, SLES 15 SP1-LTSS, SLES 15 SP1-BCL +6 more 1.1.0i-14.15.1

suse advisories SUSE-SU-2021:0939-1SUSE-SU-2021:14670-1SUSE-SU-2021:14667-1SUSE-SU-2021:0793-1SUSE-SU-2021:0769-1SUSE-SU-2021:0755-1

  • openssl-1_0_0 openSUSE Tumbleweed 1.0.2u-6.2
  • openssl-1_1 openSUSE Tumbleweed 1.1.1l-1.2
  • openssl-1_0_0 openSUSE Leap 15.2 1.0.2p-lp152.8.12.1
  • openssl-1_1 openSUSE Leap 15.2 1.1.1d-lp152.7.12.1

opensuse advisories openSUSE-SU-2024:11126-1openSUSE-SU-2024:11127-1openSUSE-SU-2021:0430-1openSUSE-SU-2021:0427-1

  • edk2-ovmf AlmaLinux 8 20210527gite1999b264f1f-3.el8

almalinux advisories ALSA-2021:4198

  • openssl Rocky Linux 8 1:1.1.1k-4.el8
  • edk2 Rocky Linux 8 20210527gite1999b264f1f-3.el8

rocky linux advisories RLSA-2021:4424RLSA-2021:4198

  • openssl Alpine 3.24, Alpine 3.23, Alpine 3.22 +13 more 1.1.1j-r0
  • openssl3 Alpine 3.16, Alpine 3.15 1.1.1j-r0
  • openssl1.1-compat Alpine 3.18, Alpine 3.17 1.1.1j-r0

alpine advisories ALPINE-CVE-2021-23841

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • shim-unsigned-x64 Azure Linux 3.0 15.8-5
  • shim-unsigned-aarch64 Azure Linux 3.0 15.8-5

azure linux advisories AZL-40768AZL-41571

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

  • openssl Arch Linux 1.1.1.j-1

arch linux advisories AVG-1581

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2021-23841 updated cvss 5.9

openssl: NULL pointer dereference in X509_issuer_and_serial_hash()

  • Red Hat Advanced Cluster Management for Kubernetes 2 management-ingress-rhel7
    affected: workaround, no fix available
  • Red Hat Enterprise Linux 6 openssl, openssl098e, openssl-perl
    affected: workaround, no fix planned “Out of support scope”
  • Red Hat Enterprise Linux 7 ovmf, OVMF, AAVMF, openssl098e
    affected: workaround, no fix available, no fix planned “Will not fix”
  • Red Hat Enterprise Linux 8 compat-openssl10
    affected: workaround, no fix planned “Will not fix”
  • Red Hat JBoss Enterprise Application Platform 6 openssl
    affected: workaround, no fix planned “Out of support scope”
  • Red Hat Enterprise Linux AppStream (v. 8) edk2 20210527gite1999b264f1f-3.el8, edk2-ovmf 20210527gite1999b264f1f-3.el8, edk2-aarch64 20210527gite1999b264f1f-3.el8
    fixed: vendor fix RHSA-2021:4198
  • Red Hat Enterprise Linux BaseOS (v. 8) openssl 1.1.1k-4.el8, openssl-libs 1.1.1k-4.el8, openssl-perl 1.1.1k-4.el8
    fixed: vendor fix RHSA-2021:4424
  • Red Hat Enterprise Linux Client (v. 7) openssl 1.0.2k-22.el7_9, openssl-libs 1.0.2k-22.el7_9 Red Hat Enterprise Linux Client Optional (v. 7) openssl-perl 1.0.2k-22.el7_9 Red Hat Enterprise Linux ComputeNode Optional (v. 7) openssl-perl 1.0.2k-22.el7_9 Red Hat Enterprise Linux Server (v. 7) openssl 1.0.2k-22.el7_9, openssl-libs 1.0.2k-22.el7_9 Red Hat Enterprise Linux Server Optional (v. 7) openssl-perl 1.0.2k-22.el7_9 Red Hat Enterprise Linux Workstation (v. 7) openssl 1.0.2k-22.el7_9, openssl-libs 1.0.2k-22.el7_9
    +1 more products
    Red Hat Enterprise Linux Workstation Optional (v. 7) openssl-perl 1.0.2k-22.el7_9
    fixed: vendor fix RHSA-2021:3798
show 5 more
  • Red Hat JBoss Core Services
    fixed: vendor fix RHSA-2021:4613
  • Red Hat JBoss Core Services on RHEL 7 Server jbcs-httpd24-apr 1.6.3-107.jbcs.el7, jbcs-httpd24-curl 7.78.0-2.jbcs.el7, jbcs-httpd24-httpd 2.4.37-78.jbcs.el7, jbcs-httpd24-mod_md 2.0.8-40.jbcs.el7, jbcs-httpd24-libcurl 7.78.0-2.jbcs.el7, jbcs-httpd24-openssl 1.1.1g-8.jbcs.el7, +26 more Red Hat JBoss Core Services on RHEL 8 jbcs-httpd24-apr 1.6.3-107.el8jbcs, jbcs-httpd24-curl 7.78.0-2.el8jbcs, jbcs-httpd24-httpd 2.4.37-78.el8jbcs, jbcs-httpd24-mod_md 2.0.8-40.el8jbcs, jbcs-httpd24-libcurl 7.78.0-2.el8jbcs, jbcs-httpd24-openssl 1.1.1g-8.el8jbcs, +26 more
    fixed: vendor fix RHSA-2021:4614
  • Red Hat JBoss Web Server 5
    fixed: vendor fix RHSA-2021:4863
  • Red Hat JBoss Web Server 5.6 for RHEL 7 Server jws5-tomcat 9.0.50-3.redhat_00004.1.el7jws, jws5-tomcat-native 1.2.30-3.redhat_3.el7jws, jws5-tomcat-lib 9.0.50-3.redhat_00004.1.el7jws, jws5-tomcat-javadoc 9.0.50-3.redhat_00004.1.el7jws, jws5-tomcat-selinux 9.0.50-3.redhat_00004.1.el7jws, jws5-tomcat-webapps 9.0.50-3.redhat_00004.1.el7jws, +9 more Red Hat JBoss Web Server 5.6 for RHEL 8 jws5-tomcat 9.0.50-3.redhat_00004.1.el8jws, jws5-tomcat-native 1.2.30-3.redhat_3.el8jws, jws5-tomcat-lib 9.0.50-3.redhat_00004.1.el8jws, jws5-tomcat-javadoc 9.0.50-3.redhat_00004.1.el8jws, jws5-tomcat-selinux 9.0.50-3.redhat_00004.1.el8jws, jws5-tomcat-webapps 9.0.50-3.redhat_00004.1.el8jws, +7 more
    fixed: vendor fix RHSA-2021:4861
  • Red Hat Enterprise Linux 9 openssl, openssl-libs, openssl-perl
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

cisa ICSA-21-336-06 updated cvss 5.9

Hitachi Energy APM Edge

  • Hitachi Energy APM Edge 3.0, 2.0, 1.0
    affected: vendor fix, mitigation “Physically protect process control systems from direct access by unauthorized personnel.” search.abb.com

From CISA ICS and IT advisories (CSAF, https://github.com/cisagov/CSAF), a U.S. Government work; changed: reduced to products, statuses and remediations. CISA notification · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
2 y ago

Exploit prediction

7.41% chance of exploitation in the next 30 days, higher than 94% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
GitHub 3.1 5.9 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD 3.1 5.9 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD 2.0 4.3 AV:N/AC:M/Au:N/C:N/I:N/A:P
OSV 3.1 5.9 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected packages

ecosystem package affected fixed in
crates.io openssl-src
<111.14.0
>=0.0.0-0, <111.14.0
111.14.0
julia OpenSSL_jll
<1.1.10+0
1.1.10+0
julia Openresty_jll
<1.19.9+0
1.19.9+0

Affected products

  • OpenSSL OpenSSL

Classification

Weakness
  • CWE-190 Integer Overflow or Wraparound
  • CWE-476 NULL Pointer Dereference
Technology feeds

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.