CVE-2021-32686
Denial of Service in PJSIP
No known exploitation. EPSS puts it in the 81st percentile. A vendor fix is available.
What to do
The vendor has published a fix. Version details are below where the sources state them.
What it is
From the CVE record
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 PJSIP before version 2.11.1, there are a couple of issues found in the SSL socket. First, a race condition between callback and destroy, due to the accepted socket having no group lock. Second, the SSL socket parent/listener may get destroyed during handshake. Both issues were reported to happen intermittently in heavy load TLS connections. They cause a crash, resulting in a denial of service. These are fixed in version 2.11.1.
In plain language
No plain-language summary for this CVE yet.
Exploitation
Where each signal puts this CVE on the scale from published to confirmed exploited.
- CISA KEV
Not in the catalog. CISA has not confirmed exploitation.
- Public exploits
No public exploit or proof of concept found in the sources we track.
- EPSS
2.1% chance of exploitation activity in the next 30 days, which ranks it in the 81st percentile of scored CVEs.
Exploit Prediction Scoring System, FIRST.org. A probability, not a confirmation.
Lifecycle
6 events over 1798 days, from the signal feeds we watch.
- OpenVAS check added
- Patch availablerecord updated
- Publishedweakness classified, att&ck mapped
Affected products
Technical detail
CVSS 3.1 vector
Open in the CVSS calculatorCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
Scored 5.9 by NVD.
How it is reached
- Attack Vector NetworkExploitable remotely over the network without any special conditions
- Attack Complexity HighRequires specific conditions like a race condition or non-default configuration
- Privileges Required NoneNo authentication required — anyone can exploit this
- User Interaction NoneNo user interaction needed — fully automated exploitation
Scope
- Scope UnchangedImpact is limited to the vulnerable component itself
Impact if exploited
- Confidentiality NoneNo confidentiality impact
- Integrity NoneNo integrity impact
- Availability HighTotal denial of service — the component is completely unavailable
Weaknesses
ATT&CK techniques
Mapped from the weaknesses above (CWE to ATT&CK), not observed in attacks.
- Privilege EscalationT1068Exploitation for Privilege Escalationmedium confidence
Sources
References in the record
- github.com/pjsip/pjproject/commit/d5f95aa066f878b0aef6a64e60b61e8626e664cd
- github.com/pjsip/pjproject/pull/2716
- github.com/pjsip/pjproject/releases/tag/2.11.1
And 12 more references. See all after sign-in
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