CVE-2022-4450: OpenSSL

High severity, CVSS 7.5. EPSS: 20.3% chance of exploitation in the next 30 days.

The function PEM_read_bio_ex() reads a PEM file from a BIO and parses and decodes the "name" (e.g. "CERTIFICATE"), any header data and the payload data. If the function succeeds then the "name_out", "header" and "data" arguments are populated with pointers to buffers containing the relevant decoded data. The caller is responsible for freeing those buffers. It is possible to construct a PEM file that results in 0 bytes of payload data. In this case PEM_read_bio_ex() will return a failure code but will populate the header argument with a pointer to a buffer that has already been freed. If the caller also frees this buffer then a double free will occur. This will most likely lead to a crash. This could be exploited by an attacker who has the ability to supply malicious PEM files for parsing to achieve a denial of service attack. The functions PEM_read_bio() and PEM_read() are simple wrappers around PEM_read_bio_ex() and therefore these functions are also directly affected. These functions are also called indirectly by a number of other OpenSSL functions including PEM_X509_INFO_read_bio_ex() and SSL_CTX_use_serverinfo_file() which are also vulnerable. Some OpenSSL internal uses of these functions are not vulnerable because the caller does not free the header argument if PEM_read_bio_ex() returns a failure code. These locations include the PEM_read_bio_TYPE() functions as well as the decoders introduced in OpenSSL 3.0. The OpenSSL asn1parse command line application is also impacted by this issue.

Affected products

• OpenSSL OpenSSL: from 1.1.1, before 1.1.1t (fixed in 1.1.1t); from 3.0.0, before 3.0.8 (fixed in 3.0.8)
• Stormshield Stormshield Network Security: from 4.0.0, before 4.3.16 (fixed in 4.3.16); from 4.4.0, before 4.6.3 (fixed in 4.6.3)

Published 2023-02-08. Last modified 2026-06-17.