PT-2021-17165 · Asterisk+2 · Asterisk+2

Diogo Hartmann · Published 2021-02-18 · Updated 2025-02-13 · CVE-2021-26906

Positive Technologies (AI Summary)

CVSS v3.1

5.9

Medium

Base vector

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

Name of the Vulnerable Software and Affected Versions: Asterisk versions 13.38.1 and earlier, 14.x, 15.x, 16.x through 16.16.0, 17.x through 17.9.1, and 18.x through 18.2.0 Certified Asterisk versions 16.8-cert5 and earlier

Description: An issue in res pjsip session.c allows a remote server to potentially crash Asterisk by sending specific SIP responses that cause an SDP negotiation failure in PJSIP.

Recommendations: For Asterisk versions 13.38.1 and earlier, 14.x, 15.x, 16.x through 16.16.0, 17.x through 17.9.1, and 18.x through 18.2.0, update to a version that contains a fix for this issue. For Certified Asterisk versions 16.8-cert5 and earlier, update to a version that contains a fix for this issue. As a temporary workaround, consider restricting access to the PJSIP module to minimize the risk of exploitation.

Fix

Improper Resource Release

Weakness Enumeration

CWE-404

Related Identifiers

ALT-PU-2023-6874

ALT-PU-2025-2613

CVE-2021-26906

Affected Products

Alt Linux

Asterisk

Pjsip

References · 12

• https://downloads.asterisk.org/pub/security · Vendor Advisory
• https://downloads.asterisk.org/pub/security/AST-2021-005.html · Vendor Advisory
• https://nvd.nist.gov/vuln/detail/CVE-2021-26906 · Security Note
• https://issues.asterisk.org/jira/browse/ASTERISK-29196 · Vendor Advisory
• https://security-tracker.debian.org/tracker/CVE-2021-26906 · Vendor Advisory
• https://osv.dev/vulnerability/DEBIAN-CVE-2021-26906 · Vendor Advisory
• https://osv.dev/vulnerability/ALPINE-CVE-2021-26906 · Vendor Advisory
• http://seclists.org/fulldisclosure/2021/Feb/61 · Patch
• https://osv.dev/vulnerability/CVE-2021-26906 · Vendor Advisory
• https://security.alpinelinux.org/vuln/CVE-2021-26906 · Note
• http://packetstormsecurity.com/files/161477/Asterisk-Project-Security-Advisory-AST-2021-005.html · Note
• https://t.me/cibsecurity/23836 · Telegram Post