What is CVE-2021-43845?

CVE-2021-43845 is a high-severity vulnerability in Pjsip Pjproject, classified under Out-of-bounds Read. CVSS score: 8.2/10. Published 2021-12-27.

How severe is CVE-2021-43845?

High severity. CVSS v3 base score is 8.2 out of 10.

Is CVE-2021-43845 known to be exploited?

1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.

Out-of-bounds Read in Pjsip Pjproject

CVE-2021-43845

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.

Vulnerability class: Buffer Overflow

Published 2021-12-27 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 8.2 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:L.

EPSS exploit prediction

EPSS: 0.039 (90.3th percentile), scored 2026-11-03.

Low probability of exploitation in the next 30 days, but still tracked. 90th percentile — 90.3% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.036 · newest: 0.039 · change: +0.003

Affected products

Pjsip Pjproject — versions <= 2.11.1
Teluu Pjsip
Debian Linux — versions 9.0, 10.0, 11.0

Weakness classification (CWE)

CWE-125 — Out-of-bounds Read

Public proof-of-concept exploits

ARPSyndicate/cvemon

References

github.com/pjsip/pjproject/security/advisories/GHSA-r374-qrwv-86hh (Patch, Third Party Advisory)
github.com/pjsip/pjproject/pull/2924 (Exploit, Patch, Third Party Advisory, Issue Tracking)
github.com/pjsip/pjproject/commit/f74c1fc22b760d2a24369aa72c74c4a9ab985859 (Patch, Third Party Advisory)
lists.debian.org/debian-lts-announce/2022/03/msg00035.html (mailing-list, Mailing List, Third Party Advisory)
security.gentoo.org/glsa/202210-37 (vendor-advisory, Third Party Advisory)
lists.debian.org/debian-lts-announce/2022/11/msg00021.html (mailing-list, Mailing List, Third Party Advisory)
www.debian.org/security/2022/dsa-5285 (vendor-advisory, Third Party Advisory)
lists.debian.org/debian-lts-announce/2023/08/msg00038.html (mailing-list)
af854a3a-2127-422b-91ae-364da2661108

Frequently asked questions

What is CVE-2021-43845?: CVE-2021-43845 is a high-severity vulnerability in Pjsip Pjproject, classified under Out-of-bounds Read. CVSS score: 8.2/10. Published 2021-12-27.
How severe is CVE-2021-43845?: High severity. CVSS v3 base score is 8.2 out of 10.
Is CVE-2021-43845 known to be exploited?: 1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.