PT-2021-3611 · Openssl+14 · Openssl+14
Tavis Ormandy
·
Published
2021-02-15
·
Updated
2026-04-27
·
CVE-2021-23841
CVSS v3.1
5.9
Medium
| Vector | AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H |
Name of the Vulnerable Software and Affected Versions
OpenSSL versions 1.1.1i and below
OpenSSL versions 1.0.2x and below
Description
The issue is related to the
X509 issuer and serial hash() function, which 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, potentially resulting in a NULL pointer dereference and a crash, leading to a potential denial of service attack. This function 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. Additionally, calls to EVP CipherUpdate, EVP EncryptUpdate, and EVP DecryptUpdate may overflow the output length argument in some cases, causing applications to behave incorrectly or crash.Recommendations
For OpenSSL versions 1.1.1i and below, upgrade to OpenSSL 1.1.1j.
For OpenSSL versions 1.0.2x and below, premium support customers should upgrade to 1.0.2y, while other users should upgrade to 1.1.1j.
As a temporary workaround, consider avoiding the use of the
X509 issuer and serial hash() function on certificates from untrusted sources until a patch is available.Exploit
Fix
DoS
NULL Pointer Dereference
Integer Overflow
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Related Identifiers
Affected Products
Alt Linux
Almalinux
Astra Linux
Centos
Freebsd
Ibm Aix
Linuxmint
Apple Macos
Mysql Server
Openssl
Red Hat
Red Os
Rocky Linux
Suse
Ubuntu