Double Free Affecting openssl-libs package, versions <1:1.1.1k-9.el8_7


0.0
high

Snyk CVSS

    Attack Complexity Low
    Availability High

    Threat Intelligence

    EPSS 0.12% (46th percentile)
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NVD
7.5 high
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SUSE
5.9 medium
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Red Hat
7.5 high

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  • Snyk ID SNYK-CENTOS8-OPENSSLLIBS-3315617
  • published 8 Feb 2023
  • disclosed 7 Feb 2023

How to fix?

Upgrade Centos:8 openssl-libs to version 1:1.1.1k-9.el8_7 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream openssl-libs package and not the openssl-libs package as distributed by Centos. See How to fix? for Centos:8 relevant fixed versions and status.

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.