CVE-2021-44538
9.8 · CRITICALOverview
CVE-2021-44538 is a critical-severity vulnerability affecting matrix element. 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 and patches from matrix. Update element to the latest patched version. 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.
Affected Products
| Vendor | Product | Versions | Status |
|---|---|---|---|
| matrix | element | >= 0, < 1.9.7 | Affected |
| matrix | javascript_sdk | >= 2.4.2, < 15.2.1 | Affected |
| matrix | olm | >= 3.1.4, < 3.2.8 | Affected |
| schildi | schildichat | >= 0, < 1.9.7-sc1 | Affected |
| cinny_project | cinny | >= 0, < 1.6.0 | Affected |
References
Frequently Asked Questions
What is CVE-2021-44538?
CVE-2021-44538 is a critical-severity vulnerability affecting matrix element. 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 and patches from matrix. Update element to the latest patched version. 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's AI-powered security agents can automatically detect CVE-2021-44538 across your infrastructure using autonomous pentesting, DAST scanning, and HackBrowser. The platform continuously monitors for known vulnerabilities and provides actionable remediation guidance prioritized by real-world exploitability.
How CyberStrike Helps
AI agents map your attack surface to find vulnerabilities like this one.
Automated penetration testing that runs continuously, not just quarterly.
AI-driven PR review catches vulnerable dependencies before they ship.
Browser-based exploitation validates findings with real proof-of-concept.
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