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Vulnerability details: VCID-nzyb-tgbf-37ep
Vulnerability ID VCID-nzyb-tgbf-37ep
Aliases CVE-2021-26717
Summary An issue was discovered in Sangoma Asterisk 16.x before 16.16.1, 17.x before 17.9.2, and 18.x before 18.2.1 and Certified Asterisk before 16.8-cert6. When re-negotiating for T.38, if the initial remote response was delayed just enough, Asterisk would send both audio and T.38 in the SDP. If this happened, and the remote responded with a declined T.38 stream, then Asterisk would crash.
Status Published
Exploitability 0.5
Weighted Severity 6.8
Risk 3.4
Affected and Fixed Packages Package Details
Weaknesses (0)
There are no known CWE.
System Score Found at
epss 0.0044 https://api.first.org/data/v1/epss?cve=CVE-2021-26717
epss 0.0044 https://api.first.org/data/v1/epss?cve=CVE-2021-26717
epss 0.0044 https://api.first.org/data/v1/epss?cve=CVE-2021-26717
epss 0.0044 https://api.first.org/data/v1/epss?cve=CVE-2021-26717
epss 0.0044 https://api.first.org/data/v1/epss?cve=CVE-2021-26717
epss 0.0044 https://api.first.org/data/v1/epss?cve=CVE-2021-26717
epss 0.0044 https://api.first.org/data/v1/epss?cve=CVE-2021-26717
epss 0.0044 https://api.first.org/data/v1/epss?cve=CVE-2021-26717
epss 0.0044 https://api.first.org/data/v1/epss?cve=CVE-2021-26717
epss 0.0044 https://api.first.org/data/v1/epss?cve=CVE-2021-26717
epss 0.0044 https://api.first.org/data/v1/epss?cve=CVE-2021-26717
epss 0.0044 https://api.first.org/data/v1/epss?cve=CVE-2021-26717
epss 0.0044 https://api.first.org/data/v1/epss?cve=CVE-2021-26717
epss 0.0044 https://api.first.org/data/v1/epss?cve=CVE-2021-26717
epss 0.0044 https://api.first.org/data/v1/epss?cve=CVE-2021-26717
cvssv2 5.0 https://nvd.nist.gov/vuln/detail/CVE-2021-26717
cvssv3.1 7.5 https://nvd.nist.gov/vuln/detail/CVE-2021-26717
Reference id Reference type URL
http://packetstormsecurity.com/files/161471/Asterisk-Project-Security-Advisory-AST-2021-002.html
https://api.first.org/data/v1/epss?cve=CVE-2021-26717
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-26717
https://downloads.asterisk.org/pub/security/
https://downloads.asterisk.org/pub/security/AST-2021-002.html
http://seclists.org/fulldisclosure/2021/Feb/58
https://issues.asterisk.org/jira/browse/ASTERISK-29203
983157 https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=983157
cpe:2.3:a:digium:asterisk:*:*:*:*:*:*:*:* https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=cpe:2.3:a:digium:asterisk:*:*:*:*:*:*:*:*
cpe:2.3:a:digium:certified_asterisk:16.8:-:*:*:*:*:*:* https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=cpe:2.3:a:digium:certified_asterisk:16.8:-:*:*:*:*:*:*
cpe:2.3:a:digium:certified_asterisk:16.8:cert1-rc1:*:*:*:*:*:* https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=cpe:2.3:a:digium:certified_asterisk:16.8:cert1-rc1:*:*:*:*:*:*
cpe:2.3:a:digium:certified_asterisk:16.8:cert1-rc2:*:*:*:*:*:* https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=cpe:2.3:a:digium:certified_asterisk:16.8:cert1-rc2:*:*:*:*:*:*
cpe:2.3:a:digium:certified_asterisk:16.8:cert1-rc3:*:*:*:*:*:* https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=cpe:2.3:a:digium:certified_asterisk:16.8:cert1-rc3:*:*:*:*:*:*
cpe:2.3:a:digium:certified_asterisk:16.8:cert1-rc4:*:*:*:*:*:* https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=cpe:2.3:a:digium:certified_asterisk:16.8:cert1-rc4:*:*:*:*:*:*
cpe:2.3:a:digium:certified_asterisk:16.8:cert2:*:*:*:*:*:* https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=cpe:2.3:a:digium:certified_asterisk:16.8:cert2:*:*:*:*:*:*
cpe:2.3:a:digium:certified_asterisk:16.8:cert3:*:*:*:*:*:* https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=cpe:2.3:a:digium:certified_asterisk:16.8:cert3:*:*:*:*:*:*
cpe:2.3:a:digium:certified_asterisk:16.8:cert4:*:*:*:*:*:* https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=cpe:2.3:a:digium:certified_asterisk:16.8:cert4:*:*:*:*:*:*
cpe:2.3:a:digium:certified_asterisk:16.8:cert4-rc1:*:*:*:*:*:* https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=cpe:2.3:a:digium:certified_asterisk:16.8:cert4-rc1:*:*:*:*:*:*
cpe:2.3:a:digium:certified_asterisk:16.8:cert4-rc2:*:*:*:*:*:* https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=cpe:2.3:a:digium:certified_asterisk:16.8:cert4-rc2:*:*:*:*:*:*
cpe:2.3:a:digium:certified_asterisk:16.8:cert4-rc3:*:*:*:*:*:* https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=cpe:2.3:a:digium:certified_asterisk:16.8:cert4-rc3:*:*:*:*:*:*
cpe:2.3:a:digium:certified_asterisk:16.8:cert4-rc4:*:*:*:*:*:* https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=cpe:2.3:a:digium:certified_asterisk:16.8:cert4-rc4:*:*:*:*:*:*
cpe:2.3:a:digium:certified_asterisk:16.8:cert5:*:*:*:*:*:* https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=cpe:2.3:a:digium:certified_asterisk:16.8:cert5:*:*:*:*:*:*
CVE-2021-26717 https://nvd.nist.gov/vuln/detail/CVE-2021-26717
No exploits are available.
Vector: AV:N/AC:L/Au:N/C:N/I:N/A:P Found at https://nvd.nist.gov/vuln/detail/CVE-2021-26717
Exploitability (E) Access Vector (AV) Access Complexity (AC) Authentication (Au) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

high

functional

unproven

proof_of_concept

not_defined

local

adjacent_network

network

high

medium

low

multiple

single

none

none

partial

complete

none

partial

complete

none

partial

complete
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Found at https://nvd.nist.gov/vuln/detail/CVE-2021-26717
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none
Exploit Prediction Scoring System (EPSS)
Percentile 0.62251
EPSS Score 0.0044
Published At Aug. 9, 2025, 12:55 p.m.
Date Actor Action Source VulnerableCode Version
2025-07-31T08:28:07.108065+00:00 Alpine Linux Importer Import https://secdb.alpinelinux.org/v3.14/main.json 37.0.0