CVE-2021-44538

NameCVE-2021-44538
DescriptionThe olm_session_describe function in Matrix libolm before 3.2.7 is vulnerable to a buffer overflow. The Olm session object represents a cryptographic channel between two parties. Therefore, its state is partially controllable by the remote party of the channel. Attackers can construct a crafted sequence of messages to manipulate the state of the receiver's session in such a way that, for some buffer sizes, a buffer overflow happens on a call to olm_session_describe. Furthermore, safe buffer sizes were undocumented. The overflow content is partially controllable by the attacker and limited to ASCII spaces and digits. The known affected products are Element Web And SchildiChat Web.
SourceCVE (at NVD; CERT, LWN, oss-sec, fulldisc, bugtraq, EDB, Metasploit, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, Mageia, GitHub code/issues, web search, more)
ReferencesDLA-2874-1, DSA-5034-1
NVD severityhigh
Debian Bugs866502, 1001664

Vulnerable and fixed packages

The table below lists information on source packages.

Source PackageReleaseVersionStatus
node-matrix-js-sdk (PTS)buster0.9.2-1vulnerable
bullseye9.3.0+~cs9.9.16-2vulnerable
sid9.11.0+~cs9.9.16-1vulnerable
olm (PTS)buster2.2.2+git20170526.0fd768e+dfsg-1fixed
bullseye3.2.1~dfsg-7vulnerable
bookworm3.2.10~dfsg-3fixed
sid3.2.10~dfsg-4fixed
thunderbird (PTS)stretch1:68.10.0-1~deb9u1vulnerable
stretch (security)1:91.5.0-1~deb9u1fixed
buster1:78.14.0-1~deb10u1vulnerable
buster (security)1:91.5.0-2~deb10u1fixed
bullseye1:78.14.0-1~deb11u1vulnerable
bullseye (security)1:91.5.0-2~deb11u1fixed
bookworm, sid1:91.5.0-2fixed

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

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs
element-webITP866502
node-matrix-js-sdksource(unstable)(unfixed)
olmsourcebuster(not affected)
olmsource(unstable)3.2.8~dfsg-11001664
thunderbirdsourcestretch1:91.4.1-1~deb9u1DLA-2874-1
thunderbirdsourcebuster1:91.4.1-1~deb10u1DSA-5034-1
thunderbirdsourcebullseye1:91.4.1-1~deb11u1DSA-5034-1
thunderbirdsource(unstable)1:91.4.1-1

Notes

[bullseye] - olm <no-dsa> (Minor issue)
[buster] - olm <not-affected> (Vulnerable code introduced later)
https://www.mozilla.org/en-US/security/advisories/mfsa2021-55/#CVE-2021-44538
https://matrix.org/blog/2021/12/13/disclosure-buffer-overflow-in-libolm-and-matrix-js-sdk/
Introduced by: https://gitlab.matrix.org/matrix-org/olm/-/commit/39a1ee0b18f0fced6d7bc293cc9a46ea70ec9e96 (3.1.4)
Fixed by: https://gitlab.matrix.org/matrix-org/olm/-/commit/c23ce70fc66c26db5839ddb5a3b46d4c3d3abed6 (3.2.8)

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