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CVE-2021-44538

9.8 · CRITICAL

The olm_session_describe function in Matrix libolm before 3.2.7 is vulnerable to a buffer overflow.

Published Dec 14, 2021CWE-119EPSS 1.98%

Overview

CVE-2021-44538 is a critical-severity vulnerability. It was published on December 14, 2021 and has a CVSS 3.1 base score of 9.8 (CRITICAL).

This vulnerability has a CVSS 3.1 base score of 9.8, rated CRITICAL. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.

Technical description

The 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.

Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

References

Refgitlab.matrix.org/matrix-org/olm/-/tagsReflists.debian.org/debian-lts-announce/2022/01/msg00001.htmlRefmatrix.org/blog/2021/12/13/disclosure-buffer-overflow-in-libolm-and-matrix-js-sdkRefwww.debian.org/security/2022/dsa-5034Refgitlab.matrix.org/matrix-org/olm/-/tagsReflists.debian.org/debian-lts-announce/2022/01/msg00001.htmlRefmatrix.org/blog/2021/12/13/disclosure-buffer-overflow-in-libolm-and-matrix-js-sdkRefwww.debian.org/security/2022/dsa-5034

How CyberStrike helps

Frequently asked questions

What is CVE-2021-44538?

CVE-2021-44538 is a critical-severity vulnerability. It was published on December 14, 2021 and has a CVSS 3.1 base score of 9.8 (CRITICAL).

How severe is CVE-2021-44538?

This vulnerability has a CVSS 3.1 base score of 9.8, rated CRITICAL. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.

How do I fix or remediate CVE-2021-44538?

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

How can CyberStrike help with CVE-2021-44538?

CyberStrike is an open-source, AI-augmented pentesting engine. Rather than flag a version number, it tests whether an issue like CVE-2021-44538 is actually reachable in your own applications and APIs, then verifies each finding before reporting it. That tells you if the weakness is a real, exploitable risk in your environment or a false positive you can safely deprioritize.

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