Vulnerability · Published Feb 16, 2021 · Assigned by openssl
CVE-2021-23841Null pointer deref in X509_issuer_and_serial_hash()
Medium 5.9
In plain English
A medium-severity security flaw in OpenSSL from OpenSSL. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 7.4% (higher than 94% of all known vulnerabilities). Ready-made attack tooling exists: public proof-of-concept code. Fixed versions are available - upgrade the affected package.
Official 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).
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| AlmaLinux:8 | edk2-ovmf | 20210527gite1999b264f1f-3.el8 | ALSA-2021:4198 |
| Alpine:v3.20 | openssl | 1.1.1j-r0 | ALPINE-CVE-2021-23841 |
| Alpine:v3.21 | openssl | 1.1.1j-r0 | ALPINE-CVE-2021-23841 |
| Alpine:v3.22 | openssl | 1.1.1j-r0 | ALPINE-CVE-2021-23841 |
| Alpine:v3.23 | openssl | 1.1.1j-r0 | ALPINE-CVE-2021-23841 |
| Alpine:v3.24 | openssl | 1.1.1j-r0 | ALPINE-CVE-2021-23841 |
| Debian:12 | openssl | 1.1.1j-1 | DEBIAN-CVE-2021-23841 |
| Debian:13 | openssl | 1.1.1j-1 | DEBIAN-CVE-2021-23841 |
| Debian:14 | openssl | 1.1.1j-1 | DEBIAN-CVE-2021-23841 |
| Rocky Linux:8 | edk2 | 0:20210527gite1999b264f1f-3.el8 | RLSA-2021:4198 |
| Rocky Linux:8 | openssl | 1:1.1.1k-4.el8 | RLSA-2021:4424 |
Affected products (as reported)
References
- https://www.openssl.org/news/secadv/20210216.txt
- https://git.openssl.org/gitweb/?p=openssl.git%3Ba=commitdiff%3Bh=122a19ab48091c657f7cb1fb3af9fc07bd557bbf
- https://git.openssl.org/gitweb/?p=openssl.git%3Ba=commitdiff%3Bh=8252ee4d90f3f2004d3d0aeeed003ad49c9a7807
- DSA-4855 vendor-advisory
- GLSA-202103-03 vendor-advisory
- 20210526 APPLE-SA-2021-05-25-2 macOS Big Sur 11.4 mailing-list
- 20210526 APPLE-SA-2021-05-25-5 Safari 14.1.1 mailing-list
- 20210526 APPLE-SA-2021-05-25-1 iOS 14.6 and iPadOS 14.6 mailing-list
- https://www.oracle.com/security-alerts/cpuApr2021.html
- https://www.tenable.com/security/tns-2021-09
- https://security.netapp.com/advisory/ntap-20210513-0002/
- https://security.netapp.com/advisory/ntap-20210219-0009/
- https://www.tenable.com/security/tns-2021-03
- https://support.apple.com/kb/HT212529
- https://support.apple.com/kb/HT212528
- https://support.apple.com/kb/HT212534
- https://www.oracle.com//security-alerts/cpujul2021.html
- https://kb.pulsesecure.net/articles/Pulse_Security_Advisories/SA44846
- https://www.oracle.com/security-alerts/cpuoct2021.html
- https://www.oracle.com/security-alerts/cpuapr2022.html
- https://cert-portal.siemens.com/productcert/pdf/ssa-637483.pdf
- https://security.netapp.com/advisory/ntap-20240621-0006/