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.
Published 2023-02-08 20:15:24
Updated 2024-02-04 09:15:09
View at NVD,
Vulnerability category: Memory CorruptionDenial of service

Exploit prediction scoring system (EPSS) score for CVE-2022-4450

Probability of exploitation activity in the next 30 days: 0.10%

Percentile, the proportion of vulnerabilities that are scored at or less: ~ 41 % EPSS Score History EPSS FAQ

CVSS scores for CVE-2022-4450

Base Score Base Severity CVSS Vector Exploitability Score Impact Score Score Source

CWE ids for CVE-2022-4450

  • The product calls free() twice on the same memory address, potentially leading to modification of unexpected memory locations.
    Assigned by: (Primary)

References for CVE-2022-4450

Products affected by CVE-2022-4450

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