DescriptionThe 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.
SourceCVE (at NVD; CERT, LWN, oss-sec, fulldisc, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)
ReferencesDLA-3325-1, DSA-5343-1

Vulnerable and fixed packages

The table below lists information on source packages.

Source PackageReleaseVersionStatus
openssl (PTS)jessie, jessie (lts)1.0.1t-1+deb8u21fixed
stretch (security)1.1.0l-1~deb9u6fixed
stretch (lts), stretch1.1.0l-1~deb9u9fixed
buster (security)1.1.1n-0+deb10u6fixed
bullseye (security)1.1.1n-0+deb11u5fixed
bookworm (security), bookworm3.0.11-1~deb12u2fixed
sid, trixie3.1.5-1fixed
openssl1.0 (PTS)stretch (security)1.0.2u-1~deb9u7fixed
stretch (lts), stretch1.0.2u-1~deb9u9fixed

The information below is based on the following data on fixed versions.

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs
opensslsourcejessie(not affected)
opensslsourcestretch(not affected)
openssl1.0source(unstable)(not affected)

Notes;a=commit;h=63bcf189be73a9cc1264059bed6f57974be74a83 (openssl-3.0.8);a=commit;h=bbcf509bd046b34cca19c766bbddc31683d0858b (OpenSSL_1_1_1t)
[stretch] - openssl <not-affected> (Vulnerable code introduced later)
[jessie] - openssl <not-affected> (Vulnerable code introduced later)
- openssl1.0 <not-affected> (Vulnerable code introduced later)

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