CVE-2021-44538 : Security Advisory and Response

The olm_session_describe function in Matrix libolm before 3.2.7 is vulnerable to a buffer overflow, potentially allowing attackers to manipulate the state of a cryptographic channel.

Understanding CVE-2021-44538

What is CVE-2021-44538?

The CVE-2021-44538 vulnerability lies in the olm_session_describe function in Matrix libolm before version 3.2.7. This function manages the state of cryptographic channels between parties, allowing potential exploitation.

The Impact of CVE-2021-44538

The vulnerability enables attackers to trigger a buffer overflow by manipulating a receiver's session state through crafted message sequences, affecting specific buffer sizes. The affected products include Element Web and SchildiChat Web.

Technical Details of CVE-2021-44538

Vulnerability Description

The olm_session_describe function in Matrix libolm prior to 3.2.7 allows remote attackers to trigger a buffer overflow, potentially manipulating the state of the receiver's session.

Affected Systems and Versions

Product: N/A
Vendor: N/A
Versions: N/A (affected)

Exploitation Mechanism

Attackers can exploit the vulnerability by sending manipulated messages to alter the receiver's session state.
Crafted message sequences can lead to buffer overflows in specific buffer sizes.

Mitigation and Prevention

Immediate Steps to Take

Update to version 3.2.7 or later to mitigate the vulnerability.
Monitor for any unusual activity on the affected systems.

Long-Term Security Practices

Regularly update software and libraries to latest versions.
Implement secure coding practices to prevent buffer overflow vulnerabilities.

Patching and Updates

Apply security patches provided by the software vendor promptly to address the vulnerability.