CVE-2021-26906

MEDIUM
Published Feb 18, 20215y ago · Modified Jun 17, 20262w ago
5.9 CVSS 3.1
Medium
Find Similar
Published Feb 18, 2021 5y ago
Last Modified Jun 17, 2026 2w ago

Description

An issue was discovered in res_pjsip_session.c in Digium Asterisk through 13.38.1; 14.x, 15.x, and 16.x through 16.16.0; 17.x through 17.9.1; and 18.x through 18.2.0, and Certified Asterisk through 16.8-cert5. An SDP negotiation vulnerability in PJSIP allows a remote server to potentially crash Asterisk by sending specific SIP responses that cause an SDP negotiation failure.

CVSS Details

Base Score
5.9
Exploitability
2.2
Impact
3.6
Vector string
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
Attack Vector Network
Attack Complexity High
Privileges Required None
User Interaction None
Scope Unchanged
Confidentiality None
Integrity None
Availability High

Threat Intelligence

No active exploitation signals — not in CISA KEV and no EPSS score yet.

Exploit & Patch Status
No Known Exploit
Patch Available

Weaknesses 1

CWE-404

Affected Products 17

VendorProductVersionRange
digiumasterisk*≥13.0.0  –  <13.38.2
digiumasterisk*≥16.0.0  –  <16.16.1
digiumasterisk*≥17.0.0  –  <17.9.2
digiumasterisk*≥18.0  –  <18.2.1
digiumcertified_asterisk16.8any
digiumcertified_asterisk16.8any
digiumcertified_asterisk16.8any
digiumcertified_asterisk16.8any
digiumcertified_asterisk16.8any
digiumcertified_asterisk16.8any
digiumcertified_asterisk16.8any
digiumcertified_asterisk16.8any
digiumcertified_asterisk16.8any
digiumcertified_asterisk16.8any
digiumcertified_asterisk16.8any
digiumcertified_asterisk16.8any
digiumcertified_asterisk16.8any

References 5

  • packetstormsecurity.com http://packetstormsecurity.com/files/161477/Asterisk-Project-Security-Advisory-AST-2021-005.html
    Third Party Advisory
  • seclists.org http://seclists.org/fulldisclosure/2021/Feb/61
    Mailing ListPatchThird Party Advisory
  • downloads.asterisk.org https://downloads.asterisk.org/pub/security/
    Vendor Advisory
  • downloads.asterisk.org https://downloads.asterisk.org/pub/security/AST-2021-005.html
    Vendor Advisory
  • issues.asterisk.org https://issues.asterisk.org/jira/browse/ASTERISK-29196
    Issue TrackingPatchVendor Advisory

Remediation

  • seclists.org http://seclists.org/fulldisclosure/2021/Feb/61
    Mailing ListPatchThird Party Advisory
  • issues.asterisk.org https://issues.asterisk.org/jira/browse/ASTERISK-29196
    Issue TrackingPatchVendor Advisory