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Vulnerability record · CVE-2021-37706 · published 22 December 2021

CVE-2021-37706: Teluu pjsip vulnerability

Teluu · Pjsip

PJSIP is a free and open source multimedia communication library written in C language implementing standard based protocols such as SIP, SDP, RTP, STUN, TURN, and ICE. In affected versions if the incoming STUN message contains an ERROR-CODE attribute, the header length is not checked before performing a subtraction operation, potentially resulting in an integer underflow scenario. This issue affects all users that use STUN. A malicious actor located within the victim’s network may forge and send a specially crafted UDP (STUN) message that could remotely execute arbitrary code on the victim’s machine. Users are advised to upgrade as soon as possible. There are no known workarounds.

9.8 CVSS 3.1 Critical EPSS 4.6% · top 8.7% CWE-191 · CWE-191
9.8CVSS 3.1 base score, v2 9.3
4.6%EPSS exploitation probability, 30 days
NoNot in CISA KEV
4Affected product versions listed by NVD
19References
17 Jun 2026Last modified by NVD

Description

PJSIP is a free and open source multimedia communication library written in C language implementing standard based protocols such as SIP, SDP, RTP, STUN, TURN, and ICE. In affected versions if the incoming STUN message contains an ERROR-CODE attribute, the header length is not checked before performing a subtraction operation, potentially resulting in an integer underflow scenario. This issue affects all users that use STUN. A malicious actor located within the victim’s network may forge and send a specially crafted UDP (STUN) message that could remotely execute arbitrary code on the victim’s machine. Users are advised to upgrade as soon as possible. There are no known workarounds.

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

Affected products

4 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
http://packetstormsecurity.com/files/166225/Asterisk-Project-Security-Advisory-AST-2022-004.html Third Party AdvisoryVDB Entry
http://seclists.org/fulldisclosure/2022/Mar/0 Mailing ListPatchThird Party Advisory
https://github.com/pjsip/pjproject/commit/15663e3f37091069b8c98a7fce680dc04bc8e865 PatchThird Party Advisory
https://github.com/pjsip/pjproject/security/advisories/GHSA-2qpg-f6wf-w984 PatchThird Party Advisory
https://lists.debian.org/debian-lts-announce/2022/03/msg00035.html Mailing ListThird Party Advisory
https://lists.debian.org/debian-lts-announce/2022/11/msg00021.html Mailing ListThird Party Advisory
https://lists.debian.org/debian-lts-announce/2023/08/msg00038.html
https://security.gentoo.org/glsa/202210-37 Third Party Advisory
https://www.debian.org/security/2022/dsa-5285 Third Party Advisory
http://packetstormsecurity.com/files/166225/Asterisk-Project-Security-Advisory-AST-2022-004.html Third Party AdvisoryVDB Entry
http://seclists.org/fulldisclosure/2022/Mar/0 Mailing ListPatchThird Party Advisory
https://github.com/pjsip/pjproject/commit/15663e3f37091069b8c98a7fce680dc04bc8e865 PatchThird Party Advisory
https://github.com/pjsip/pjproject/security/advisories/GHSA-2qpg-f6wf-w984 PatchThird Party Advisory
https://lists.debian.org/debian-lts-announce/2022/03/msg00035.html Mailing ListThird Party Advisory
https://lists.debian.org/debian-lts-announce/2022/11/msg00021.html Mailing ListThird 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/202210-37 Third Party Advisory
https://www.debian.org/security/2022/dsa-5285 Third Party Advisory

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Source: NIST National Vulnerability Database (record CVE-2021-37706), CISA KEV, FIRST EPSS (scores of 2026-09-27). This page is refreshed as NVD updates the record.