CVE-2021-43845

Name: CVE-2021-43845
Creator: NVD / NIST
Published: 2021-12-27T18:15:07.46+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

CRITICALCVSS 9.1/10EPSS 3.72%

Last modified Jun 17, 2026

CVE-2021-43845 is a critical-severity vulnerability rated 9.1/10 on the CVSS scale. PJSIP is a free and open source multimedia communication library. In version 2.11.1 and prior, if incoming RTCP XR message contain block, the data field is not checked against the received packet size, potentially resulting in an out-of-bound read access. EPSS estimates a 3.72% chance of exploitation in the next 30 days.

Description

PJSIP is a free and open source multimedia communication library. In version 2.11.1 and prior, if incoming RTCP XR message contain block, the data field is not checked against the received packet size, potentially resulting in an out-of-bound read access. This affects all users that use PJMEDIA and RTCP XR. A malicious actor can send a RTCP XR message with an invalid packet size.

Metrics

CVSS 3.1

9.1/10

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

EPSS Probability

3.72%

88.4th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions
Teluu	Pjsip	<= 2.11.1
Debian	Debian Linux	9.0
Debian	Debian Linux	10.0
Debian	Debian Linux	11.0

References

https://github.com/pjsip/pjproject/commit/f74c1fc22b760d2a24369aa72c74c4a9ab985859Patch, Third Party Advisory
https://github.com/pjsip/pjproject/pull/2924Exploit, Issue Tracking, Patch, Third Party Advisory
https://github.com/pjsip/pjproject/security/advisories/GHSA-r374-qrwv-86hhPatch, Third Party Advisory
https://lists.debian.org/debian-lts-announce/2022/03/msg00035.htmlMailing List, Third Party Advisory
https://lists.debian.org/debian-lts-announce/2022/11/msg00021.htmlMailing List, Third Party Advisory
https://lists.debian.org/debian-lts-announce/2023/08/msg00038.html
https://security.gentoo.org/glsa/202210-37Third Party Advisory
https://www.debian.org/security/2022/dsa-5285Third Party Advisory
https://github.com/pjsip/pjproject/commit/f74c1fc22b760d2a24369aa72c74c4a9ab985859Patch, Third Party Advisory
https://github.com/pjsip/pjproject/pull/2924Exploit, Issue Tracking, Patch, Third Party Advisory
https://github.com/pjsip/pjproject/security/advisories/GHSA-r374-qrwv-86hhPatch, Third Party Advisory
https://lists.debian.org/debian-lts-announce/2022/03/msg00035.htmlMailing List, Third Party Advisory
https://lists.debian.org/debian-lts-announce/2022/11/msg00021.htmlMailing List, Third Party Advisory
https://lists.debian.org/debian-lts-announce/2023/08/msg00038.html
https://lists.debian.org/debian-lts-announce/2024/09/msg00030.html
https://security.gentoo.org/glsa/202210-37Third Party Advisory
https://www.debian.org/security/2022/dsa-5285Third Party Advisory

Timeline

Published: Dec 27, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-43845?

How severe is CVE-2021-43845?

CVE-2021-43845 has a CVSS score of 9.1/10 (CRITICAL severity). The EPSS model estimates a 3.72% probability of exploitation in the next 30 days.

How do I fix CVE-2021-43845?

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-2021-43845?

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

Scan your code now

Source: NVD / NIST