CVE-2021-23841
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).
Does this matter?
Lower severity and a low EPSS score (7.41%). Track it; it rarely justifies an emergency change on its own.
Description
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).
- CVSS 3.1
- 5.9 MEDIUMCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
- EPSS
- 7.41% probability · 94th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Weakness
- CWE-476
- Affected
- openssl/openssl · debian/debian linux · tenable/nessus network monitor · tenable/tenable.sc · apple/safari · apple/ipados · apple/iphone os · apple/macos · netapp/oncommand insight · netapp/oncommand workflow automation · netapp/snapcenter · 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/jd edwards world security · oracle/mysql enterprise monitor · oracle/mysql server · +3 more
- Source
- openssl-security@openssl.org
EPSS 7.4% since 26 October 2026; no change recorded yet. The dashed line is the ten per cent mark our analysts treat as “patch before the next change window”. Points are recorded when the score first appears and whenever it moves by a percentage point or more.
References
- http://seclists.org/fulldisclosure/2021/May/67Mailing List, Third Party Advisory
- http://seclists.org/fulldisclosure/2021/May/68Mailing List, Third Party Advisory
- http://seclists.org/fulldisclosure/2021/May/70Mailing List, Third Party Advisory
- https://cert-portal.siemens.com/productcert/pdf/ssa-637483.pdfPatch, Third Party Advisory
- https://git.openssl.org/gitweb/?p=openssl.git%3Ba=commitdiff%3Bh=122a19ab48091c657f7cb1fb3af9fc07bd557bbf
- https://git.openssl.org/gitweb/?p=openssl.git%3Ba=commitdiff%3Bh=8252ee4d90f3f2004d3d0aeeed003ad49c9a7807
- https://kb.pulsesecure.net/articles/Pulse_Security_Advisories/SA44846Third Party Advisory
- https://security.gentoo.org/glsa/202103-03Third Party Advisory
- https://security.netapp.com/advisory/ntap-20210219-0009/Third Party Advisory
- https://security.netapp.com/advisory/ntap-20210513-0002/Third Party Advisory
- https://security.netapp.com/advisory/ntap-20240621-0006/
- https://support.apple.com/kb/HT212528Third Party Advisory
- https://support.apple.com/kb/HT212529Third Party Advisory
- https://support.apple.com/kb/HT212534Third Party Advisory
- https://www.debian.org/security/2021/dsa-4855Third Party Advisory
- https://www.openssl.org/news/secadv/20210216.txtVendor Advisory
- https://www.oracle.com//security-alerts/cpujul2021.htmlPatch, Third Party Advisory
- https://www.oracle.com/security-alerts/cpuApr2021.htmlPatch, Third Party Advisory
- https://www.oracle.com/security-alerts/cpuapr2022.htmlPatch, Third Party Advisory
- https://www.oracle.com/security-alerts/cpuoct2021.htmlPatch, Third Party Advisory
- https://www.tenable.com/security/tns-2021-03Third Party Advisory
- https://www.tenable.com/security/tns-2021-09Third Party Advisory
- http://seclists.org/fulldisclosure/2021/May/67Mailing List, Third Party Advisory
- http://seclists.org/fulldisclosure/2021/May/68Mailing List, Third Party Advisory
- http://seclists.org/fulldisclosure/2021/May/70Mailing List, Third Party Advisory
- https://cert-portal.siemens.com/productcert/pdf/ssa-637483.pdfPatch, Third Party Advisory
- https://git.openssl.org/gitweb/?p=openssl.git%3Ba=commitdiff%3Bh=122a19ab48091c657f7cb1fb3af9fc07bd557bbf
- https://git.openssl.org/gitweb/?p=openssl.git%3Ba=commitdiff%3Bh=8252ee4d90f3f2004d3d0aeeed003ad49c9a7807
- https://kb.pulsesecure.net/articles/Pulse_Security_Advisories/SA44846Third Party Advisory
- https://security.gentoo.org/glsa/202103-03Third Party Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.