Cyber Resilience

CVE-2021-37706

HighPublic PoC

Published: 22 December 2021

Published
22 December 2021
Modified
04 November 2025
KEV Added
Patch
CVSS Score v3.1 7.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L
EPSS Score 0.0050 66.6th percentile
Risk Priority 15 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2021-37706 is a high-severity Wrap or Wraparound (CWE-191) vulnerability in Asterisk Certified Asterisk. Its CVSS base score is 7.3 (High).

Operationally, ranked in the top 33.4% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

EU & UK References

Vulnerability details

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…

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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.

CWE(s)

Related Threats

No named actor attribution yet. ATT&CK technique mapping in progress for this CVE.

Affected Assets

teluu
pjsip
≤ 2.11.1
asterisk
certified asterisk
16.8.0 · ≤ 16.8.0
sangoma
asterisk
16.0.0 — 16.24.1 · 18.0.0 — 18.10.1 · 19.0.0 — 19.2.1
debian
debian linux
10.0, 9.0

Mitigating Controls

No mitigating controls mapped yet. The per-CVE control annotator has not reached this CVE.

References