CVE-2021-26906

mediumpriority · track · 25EPSS 0.025 · 85 %ileDEEUUS

grimoire priorityP3 · Track

Exploitable?

—

no known exploitation

Likely / severe?

2.55% (85th) EPSS

CVSS 4.3 · medium

Is it mine?

17 products

Check your exposure

Who says so?

4 sources

cnnvd · enisa_euvd · cert_bund · nvd

EPSS · scored 2026-10-27

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

Technical severity, 0–10. One row per scoring source.

5.9

010

base score 0–10 · higher = more severe · hover a vector to decode

v2.04.3mediumAV:N/AC:M/Au:N/C:N/I:N/A:Pprimary · NVD / NIST USexploitability 8.6 · impact 2.9

v3.15.9mediumCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:Hprimary · NVD / NIST USexploitability 2.2 · impact 3.6

v3.15.4mediumCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H/E:Usecondary · CVSS-BT (t0sche)

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-404USprimary

affected products (17)

Products and version ranges known to be affected.

Digium Certified Asterisk <16.8-cert6all versionscert_bundDE
Gentoo Linuxall versionscert_bundDEcpe:/o:gentoo:linux:-
Open Source Asterisk <13.38.2all versionscert_bundDE
Open Source Asterisk <16.16.1all versionscert_bundDE
Open Source Asterisk <17.9.2all versionscert_bundDE
Open Source Asterisk <18.2.1all versionscert_bundDE
Digium Certified Asterisk< 16.8-cert6cert_bundDE
Open Source Asterisk< 13.38.2cert_bundDE
Open Source Asterisk< 16.16.1cert_bundDE
Open Source Asterisk< 17.9.2cert_bundDE
Open Source Asterisk< 18.2.1cert_bundDE
n/a n/a≤ n/aenisa_euvdEU
digium asterisk13.0.0 → 13.38.2nvdUScpe:2.3:a:digium:asterisk:*:*:*:*:*:*:*:*
digium asterisk16.0.0 → 16.16.1nvdUScpe:2.3:a:digium:asterisk:*:*:*:*:*:*:*:*
digium asterisk17.0.0 → 17.9.2nvdUScpe:2.3:a:digium:asterisk:*:*:*:*:*:*:*:*
digium asterisk18.0 → 18.2.1nvdUScpe:2.3:a:digium:asterisk:*:*:*:*:*:*:*:*
digium certified asterisk= 16.8nvdUScpe:2.3:a:digium:certified_asterisk:*:*:*:*:*:*:*:*

advisories (1)

Vendor and ecosystem advisories describing this.

WID-SEC-W-2024-3633Asterisk: Mehrere Schwachstellen ermöglichen Denial of ServiceDeutsch2021-02-18csaf · cert_bundDE
Ein entfernter, anonymer Angreifer kann mehrere Schwachstellen in Asterisk ausnutzen, um einen Denial of Service Angriff durchzuführen.

also known as (3)

Other names and identifiers for this entity.

sources

Which sources assert this record, and when.

cnnvd enisa_euvd cert_bund nvd NVD CVE.org MITRE

published 2021-02-18modified 2026-06-17

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+2014 more

references (18)

External citations — patches, advisories, analysis.

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