The olm_session_describe function in Matrix libolm before 3.2.7 is vulnerable to a buffer…
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- Code execution
- Confidentiality · integrity · availability
- High · High · High
- Fix status
- No fix listed
Attack profile from CVSS 3.1 · NVD. Fix status from CNA. Impact type from CWE-119 and the CVSS impact.
Summary
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.
Why it matters now
SSVC decision points
Not available: CISA has not published SSVC decision points for this record.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| — | — | all versions | — | No fix listed | CNA |
- — Vendor— Affected all versions Fixed in — No fix listed CNA
CPE configurations NVD · 10
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:matrix:element:*:*:*:*:desktop:*:*:* | before 1.9.7 | Vulnerable | matrix-org |
| cpe:2.3:a:matrix:element:*:*:*:*:web:*:*:* | before 1.9.7 | Vulnerable | matrix-org |
| cpe:2.3:a:matrix:javascript_sdk:*:*:*:*:*:*:*:* | 2.4.2 to before 15.2.1 | Vulnerable | matrix-org |
| cpe:2.3:a:matrix:olm:*:*:*:*:*:*:*:* | 3.1.4 to before 3.2.8 | Vulnerable | matrix-org |
| cpe:2.3:a:schildi:schildichat:*:*:*:*:desktop:*:*:* | before 1.9.7-sc1 | Vulnerable | Schildi |
| cpe:2.3:a:schildi:schildichat:*:*:*:*:web:*:*:* | before 1.9.7-sc1 | Vulnerable | Schildi |
| cpe:2.3:a:cinny_project:cinny:*:*:*:*:*:*:*:* | before 1.6.0 | Vulnerable | Cinny Project |
| cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:* | 9.0 | Vulnerable | Debian |
| cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:* | 10.0 | Vulnerable | Debian |
| cpe:2.3:o:debian:debian_linux:11.0:*:*:*:*:*:*:* | 11.0 | Vulnerable | Debian |
- cpe:2.3:a:matrix:element:*:*:*:*:desktop:*:*:* Versions before 1.9.7 Vulnerable ·matrix-org
- cpe:2.3:a:matrix:element:*:*:*:*:web:*:*:* Versions before 1.9.7 Vulnerable ·matrix-org
- cpe:2.3:a:matrix:javascript_sdk:*:*:*:*:*:*:*:* Versions 2.4.2 to before 15.2.1 Vulnerable ·matrix-org
- cpe:2.3:a:matrix:olm:*:*:*:*:*:*:*:* Versions 3.1.4 to before 3.2.8 Vulnerable ·matrix-org
- cpe:2.3:a:schildi:schildichat:*:*:*:*:desktop:*:*:* Versions before 1.9.7-sc1 Vulnerable ·Schildi
- cpe:2.3:a:schildi:schildichat:*:*:*:*:web:*:*:* Versions before 1.9.7-sc1 Vulnerable ·Schildi
- cpe:2.3:a:cinny_project:cinny:*:*:*:*:*:*:*:* Versions before 1.6.0 Vulnerable ·Cinny Project
- cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:* Versions 9.0 Vulnerable ·Debian
- cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:* Versions 10.0 Vulnerable ·Debian
- cpe:2.3:o:debian:debian_linux:11.0:*:*:*:*:*:*:* Versions 11.0 Vulnerable ·Debian
Remediation
No fixed version listed by the sources yet.
Vendor assessments
Timeline
- 2026-10-02 Threatist record created from CVE-2021-44538
- 2026-10-03 Alias added: GHSA-q7f4-j236-f4hc
References
Sources
- CVE-2021-44538 · CVE Program
- CVE-2021-44538 · NVD
- FIRST EPSS
- GHSA-q7f4-j236-f4hc · GitHub Advisory Database · CC BY 4.0
- CVE-2021-44538 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences