CVE-2021-37706
No exploitation reported by the sources we read.
- Published2021-12-22
- Fixed in19.2.1 · 18.10.1 · 16.24.1
- WeaknessCWE-191
Am I affected?
Debian, Ubuntu or Red Hat sometimes backport a fix without changing the upstream version number: such a version reads « to verify », never « affected ».With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.
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.
Timeline
dates in UTC- 2021-12-2218:15CVE publishedNVD
Observed activity
isMalicious corpus · updated 2026-10-23 18:48 UTCBlock these indicators
- Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2021-37706?format=txt
- CSV export: https://api.ismalicious.com/edl/cve/CVE-2021-37706?format=csv
- TAXII collection of exploited CVEs
- The EDL and CSV take an API key on the Pro plan.
Versions per branch
NVD| Branch | Affected | Fixed in | Source |
|---|---|---|---|
| 19.x | ≥ 19.0.0, < 19.2.1 | 19.2.1 | NVD |
| 18.x | ≥ 18.0.0, < 18.10.1 | 18.10.1 | NVD |
| 16.x | ≥ 16.0.0, < 16.24.1 | 16.24.1 | NVD |
| Branch | Affected | Fixed in | Source |
|---|---|---|---|
| 16.8 | < 16.8.0 | 16.8.0 | NVD |
| 16.8 | = 16.8.0 | no fix published | NVD |
| Branch | Affected | Fixed in | Source |
|---|---|---|---|
| 9.0 | = 9.0 | no fix published | NVD |
| 10.0 | = 10.0 | no fix published | NVD |
1 more product in the sources.
as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.
Fix
- Update Sangoma asterisk to 19.2.1 · 18.10.1 · 16.24.1
Advisories and patches
- seclists.orgPatch
- github.comPatch
- github.comPatch
Detection
- Nuclei template
- none so far ProjectDiscovery
- Exploit-DB
- no entry Exploit-DB
- Proof-of-concept repositories
- none listed PoC-in-GitHub
Sources
Technical details
- CVSS v3 Vector
- CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- Published
- 2021-12-22
- Last Modified
- 2026-06-17
- NVD status
- Modified
Frequently asked questions
What is CVE-2021-37706?
Is CVE-2021-37706 actively exploited?
What is the CVSS score for CVE-2021-37706?
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