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CVE-2021-44538

CRITICALCVSS 9.8/10EPSS 1.92%

Last modified

CVE-2021-44538 is a critical-severity vulnerability rated 9.8/10 on the CVSS scale. 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. EPSS estimates a 1.92% chance of exploitation in the next 30 days.

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.

Metrics

CVSS 3.1
9.8/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS Probability
1.92%

77.3th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

VendorProductVersions
MatrixElement< 1.9.7
MatrixJavascript Sdk>= 2.4.2, < 15.2.1
MatrixOlm>= 3.1.4, < 3.2.8
SchildiSchildichat< 1.9.7-sc1
Cinny ProjectCinny< 1.6.0
DebianDebian Linux9.0
DebianDebian Linux10.0
DebianDebian Linux11.0

References

Timeline

Published
Last Modified
Status
Modified

Frequently Asked Questions

What is CVE-2021-44538?
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.
How severe is CVE-2021-44538?
CVE-2021-44538 has a CVSS score of 9.8/10 (CRITICAL severity). The EPSS model estimates a 1.92% probability of exploitation in the next 30 days.
How do I fix CVE-2021-44538?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-44538?

Run a free Strix scan to check your systems for this vulnerability.

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Source: NVD / NIST