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Vulnerability · Published Dec 14, 2021 · Assigned by mitre

CVE-2021-44538

Critical 9.8

In plain English

A critical-severity security flaw in the element-web package (Alpine). There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 2.0% (higher than 81% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS NVD)9.8Critical
Exploit odds (30 days)2.0%top 19.1% of all CVEs
Exploited in the wildNo reportsnot in CISA KEV
Attack toolingNoneno public tooling known

Official 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.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Alpine:v3.20element-web1.9.7-r0ALPINE-CVE-2021-44538
Alpine:v3.21element-web1.9.7-r0ALPINE-CVE-2021-44538
Alpine:v3.22element-web1.9.7-r0ALPINE-CVE-2021-44538
Alpine:v3.23element-web1.9.7-r0ALPINE-CVE-2021-44538
Alpine:v3.24element-web1.9.7-r0ALPINE-CVE-2021-44538
Alpine:v3.20thunderbird91.4.1-r0ALPINE-CVE-2021-44538
Alpine:v3.21thunderbird91.4.1-r0ALPINE-CVE-2021-44538
Alpine:v3.22thunderbird91.4.1-r0ALPINE-CVE-2021-44538
Alpine:v3.23thunderbird91.4.1-r0ALPINE-CVE-2021-44538
Debian:12olm3.2.8~dfsg-1DEBIAN-CVE-2021-44538
Debian:13olm3.2.8~dfsg-1DEBIAN-CVE-2021-44538
Debian:14olm3.2.8~dfsg-1DEBIAN-CVE-2021-44538
Debian:12thunderbird1:91.4.1-1DEBIAN-CVE-2021-44538
Debian:13thunderbird1:91.4.1-1DEBIAN-CVE-2021-44538
Debian:14thunderbird1:91.4.1-1DEBIAN-CVE-2021-44538
Ubuntu:22.04:LTSnode-matrix-js-sdkno fix listedUBUNTU-CVE-2021-44538
Ubuntu:24.04:LTSnode-matrix-js-sdkno fix listedUBUNTU-CVE-2021-44538
Ubuntu:22.04:LTSolmno fix listedUBUNTU-CVE-2021-44538
Ubuntu:24.04:LTSolmno fix listedUBUNTU-CVE-2021-44538
Ubuntu:25.10olmno fix listedUBUNTU-CVE-2021-44538
Ubuntu:26.04:LTSolmno fix listedUBUNTU-CVE-2021-44538
Ubuntu:26.10olmno fix listedUBUNTU-CVE-2021-44538
Ubuntu:22.04:LTSthunderbird1:91.5.0+build1-0ubuntu1UBUNTU-CVE-2021-44538

Affected products (as reported)

VendorProductVersions
n/a n/a n/a

References