Double Free Affecting openssl-1_1 package, versions <1.1.1d-150200.11.57.1



    Attack Complexity High
    Availability High

    Threat Intelligence

    EPSS 0.12% (47th percentile)
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7.5 high
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5.9 medium
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Red Hat
7.5 high

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  • Snyk ID SNYK-SLES152-OPENSSL11-3315187
  • published 8 Feb 2023
  • disclosed 7 Feb 2023

How to fix?

Upgrade SLES:15.2 openssl-1_1 to version 1.1.1d-150200.11.57.1 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream openssl-1_1 package and not the openssl-1_1 package as distributed by SLES. See How to fix? for SLES:15.2 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.