Medium
asterisk — security advisory
A stack-based buffer overflow in res_rtp_asterisk.c in Sangoma Asterisk before 16.16.1, 17.x before 17.9.2, and 18.x before 18.2.1 and Certified Asterisk before 16.8-cert6 allows an authenticated WebRTC client to cause an Asterisk crash by sending multiple hold/unhold requests in quick succession. This is caused by a signedness comparison mismatch.
- Products
- asterisk
- Affected versions
- 1:16.16.1~dfsg+~2.10-1, 1:16.16.1~dfsg-2, 1:16.16.1~dfsg-4, 1:16.16.1~dfsg-4build1, 1:18.10.0~dfsg+~cs6.10.40431411-2, 1:20.4.0~dfsg+~cs6.13.40431414-2, 1:20.5.0~dfsg+~cs6.13.40431414-1, 1:20.5.1~dfsg+~cs6.13.40431414-1, 1:20.5.2~dfsg+~cs6.13.40431414-1, 1:20.6.0~dfsg+~cs6.13.40431414-1, 1:20.6.0~dfsg+~cs6.13.40431414-2, 1:20.6.0~dfsg+~cs6.13.40431414-2build3, 1:20.6.0~dfsg+~cs6.13.40431414-2build4, 1:20.6.0~dfsg+~cs6.13.40431414-2build5, 1:22.10.0+dfsg+~cs6.17.60671434-1ubuntu2, 1:22.10.0+dfsg+~cs6.17.60671434-1ubuntu3, 1:22.2.0~dfsg+~cs6.15.60671435-2, 1:22.3.0~dfsg+~cs6.15.60671435-1, 1:22.4.1~dfsg+~cs6.15.60671435-1, 1:22.4.1~dfsg+~cs6.15.60671435-2, 1:22.5.1~dfsg+~cs6.15.60671435-1, 1:22.5.2~dfsg+~cs6.15.60671435-1
- Fixed versions
- Not specified
- CVEs
- CVE-2021-26713
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 31 Oct 2026, 01:35 UTC · Revision 1
Source evidence
A stack-based buffer overflow in res_rtp_asterisk.c in Sangoma Asterisk before 16.16.1, 17.x before 17.9.2, and 18.x before 18.2.1 and Certified Asterisk before 16.8-cert6 allows an authenticated WebRTC client to cause an Asterisk crash by sending multiple hold/unhold requests in quick succession. This is caused by a signedness comparison mismatch.
osv:UBUNTU-CVE-2021-26713
asterisk
Fixed versions: Not specified
asterisk
Fixed versions: Not specified
asterisk
Fixed versions: Not specified
asterisk
Fixed versions: Not specified
asterisk
Fixed versions: Not specified
Complete source record
{
"id": "a58114cdd82d3bcb4243371ff1c9fbc69120834f7159e5a701dd884415204e25",
"url": "https://osv.dev/vulnerability/UBUNTU-CVE-2021-26713",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "UBUNTU-CVE-2021-26713",
"summary": "A stack-based buffer overflow in res_rtp_asterisk.c in Sangoma Asterisk before 16.16.1, 17.x before 17.9.2, and 18.x before 18.2.1 and Certified Asterisk before 16.8-cert6 allows an authenticated WebRTC client to cause an Asterisk crash by sending multiple hold/unhold requests in quick succession. This is caused by a signedness comparison mismatch.",
"evidence": "osv:UBUNTU-CVE-2021-26713",
"products": [
{
"name": {
"value": "asterisk",
"evidence": "/affected/0/package/name"
},
"prerequisites": [],
"fixed_versions": [],
"affected_versions": [
{
"value": "1:16.16.1~dfsg-2",
"evidence": "/affected/0/versions"
},
{
"value": "1:16.16.1~dfsg-4",
"evidence": "/affected/0/versions"
},
{
"value": "1:16.16.1~dfsg-4build1",
"evidence": "/affected/0/versions"
},
{
"value": "1:16.16.1~dfsg+~2.10-1",
"evidence": "/affected/0/versions"
},
{
"value": "1:18.10.0~dfsg+~cs6.10.40431411-2",
"evidence": "/affected/0/versions"
}
]
},
{
"name": {
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"evidence": "/affected/1/package/name"
},
"prerequisites": [],
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"affected_versions": [
{
"value": "1:20.4.0~dfsg+~cs6.13.40431414-2",
"evidence": "/affected/1/versions"
},
{
"value": "1:20.5.0~dfsg+~cs6.13.40431414-1",
"evidence": "/affected/1/versions"
},
{
"value": "1:20.5.1~dfsg+~cs6.13.40431414-1",
"evidence": "/affected/1/versions"
},
{
"value": "1:20.5.2~dfsg+~cs6.13.40431414-1",
"evidence": "/affected/1/versions"
},
{
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"evidence": "/affected/1/versions"
},
{
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"evidence": "/affected/1/versions"
},
{
"value": "1:20.6.0~dfsg+~cs6.13.40431414-2build3",
"evidence": "/affected/1/versions"
},
{
"value": "1:20.6.0~dfsg+~cs6.13.40431414-2build4",
"evidence": "/affected/1/versions"
},
{
"value": "1:20.6.0~dfsg+~cs6.13.40431414-2build5",
"evidence": "/affected/1/versions"
}
]
},
{
"name": {
"value": "asterisk",
"evidence": "/affected/2/package/name"
},
"prerequisites": [],
"fixed_versions": [],
"affected_versions": [
{
"value": "1:22.2.0~dfsg+~cs6.15.60671435-2",
"evidence": "/affected/2/versions"
},
{
"value": "1:22.3.0~dfsg+~cs6.15.60671435-1",
"evidence": "/affected/2/versions"
},
{
"value": "1:22.4.1~dfsg+~cs6.15.60671435-1",
"evidence": "/affected/2/versions"
},
{
"value": "1:22.4.1~dfsg+~cs6.15.60671435-2",
"evidence": "/affected/2/versions"
},
{
"value": "1:22.5.1~dfsg+~cs6.15.60671435-1",
"evidence": "/affected/2/versions"
},
{
"value": "1:22.5.2~dfsg+~cs6.15.60671435-1",
"evidence": "/affected/2/versions"
}
]
},
{
"name": {
"value": "asterisk",
"evidence": "/affected/3/package/name"
},
"prerequisites": [],
"fixed_versions": [],
"affected_versions": [
{
"value": "1:22.5.2~dfsg+~cs6.15.60671435-1",
"evidence": "/affected/3/versions"
},
{
"value": "1:22.10.0+dfsg+~cs6.17.60671434-1ubuntu2",
"evidence": "/affected/3/versions"
},
{
"value": "1:22.10.0+dfsg+~cs6.17.60671434-1ubuntu3",
"evidence": "/affected/3/versions"
}
]
},
{
"name": {
"value": "asterisk",
"evidence": "/affected/4/package/name"
},
"prerequisites": [],
"fixed_versions": [],
"affected_versions": [
{
"value": "1:22.5.2~dfsg+~cs6.15.60671435-1",
"evidence": "/affected/4/versions"
}
]
}
],
"severity": "medium",
"structured": {
"id": "UBUNTU-CVE-2021-26713",
"aliases": [
"UBUNTU-CVE-2021-26713"
],
"metrics": [
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H"
},
{
"type": "Ubuntu",
"score": "medium"
}
],
"affected": [
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
}
]
}
],
"package": {
"name": "asterisk",
"purl": "pkg:deb/ubuntu/asterisk?arch=source&distro=jammy",
"ecosystem": "Ubuntu:22.04:LTS"
},
"versions": [
"1:16.16.1~dfsg-2",
"1:16.16.1~dfsg-4",
"1:16.16.1~dfsg-4build1",
"1:16.16.1~dfsg+~2.10-1",
"1:18.10.0~dfsg+~cs6.10.40431411-2"
],
"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2021/UBUNTU-CVE-2021-26713.json"
},
"ecosystem_specific": {
"binaries": [
{
"binary_name": "asterisk",
"binary_version": "1:18.10.0~dfsg+~cs6.10.40431411-2"
},
{
"binary_name": "asterisk-config",
"binary_version": "1:18.10.0~dfsg+~cs6.10.40431411-2"
},
{
"binary_name": "asterisk-dahdi",
"binary_version": "1:18.10.0~dfsg+~cs6.10.40431411-2"
},
{
"binary_name": "asterisk-mobile",
"binary_version": "1:18.10.0~dfsg+~cs6.10.40431411-2"
},
{
"binary_name": "asterisk-modules",
"binary_version": "1:18.10.0~dfsg+~cs6.10.40431411-2"
},
{
"binary_name": "asterisk-mp3",
"binary_version": "1:18.10.0~dfsg+~cs6.10.40431411-2"
},
{
"binary_name": "asterisk-mysql",
"binary_version": "1:18.10.0~dfsg+~cs6.10.40431411-2"
},
{
"binary_name": "asterisk-ooh323",
"binary_version": "1:18.10.0~dfsg+~cs6.10.40431411-2"
},
{
"binary_name": "asterisk-tests",
"binary_version": "1:18.10.0~dfsg+~cs6.10.40431411-2"
},
{
"binary_name": "asterisk-vpb",
"binary_version": "1:18.10.0~dfsg+~cs6.10.40431411-2"
}
]
}
},
{
"ranges": [
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}
],
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"purl": "pkg:deb/ubuntu/asterisk?arch=source&distro=noble",
"ecosystem": "Ubuntu:24.04:LTS"
},
"versions": [
"1:20.4.0~dfsg+~cs6.13.40431414-2",
"1:20.5.0~dfsg+~cs6.13.40431414-1",
"1:20.5.1~dfsg+~cs6.13.40431414-1",
"1:20.5.2~dfsg+~cs6.13.40431414-1",
"1:20.6.0~dfsg+~cs6.13.40431414-1",
"1:20.6.0~dfsg+~cs6.13.40431414-2",
"1:20.6.0~dfsg+~cs6.13.40431414-2build3",
"1:20.6.0~dfsg+~cs6.13.40431414-2build4",
"1:20.6.0~dfsg+~cs6.13.40431414-2build5"
],
"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2021/UBUNTU-CVE-2021-26713.json"
},
"ecosystem_specific": {
"binaries": [
{
"binary_name": "asterisk",
"binary_version": "1:20.6.0~dfsg+~cs6.13.40431414-2build5"
},
{
"binary_name": "asterisk-config",
"binary_version": "1:20.6.0~dfsg+~cs6.13.40431414-2build5"
},
{
"binary_name": "asterisk-dahdi",
"binary_version": "1:20.6.0~dfsg+~cs6.13.40431414-2build5"
},
{
"binary_name": "asterisk-mobile",
"binary_version": "1:20.6.0~dfsg+~cs6.13.40431414-2build5"
},
{
"binary_name": "asterisk-modules",
"binary_version": "1:20.6.0~dfsg+~cs6.13.40431414-2build5"
},
{
"binary_name": "asterisk-mp3",
"binary_version": "1:20.6.0~dfsg+~cs6.13.40431414-2build5"
},
{
"binary_name": "asterisk-mysql",
"binary_version": "1:20.6.0~dfsg+~cs6.13.40431414-2build5"
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{
"binary_name": "asterisk-ooh323",
"binary_version": "1:20.6.0~dfsg+~cs6.13.40431414-2build5"
},
{
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}
]
}
},
{
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}
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}
],
"package": {
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"purl": "pkg:deb/ubuntu/asterisk?arch=source&distro=questing",
"ecosystem": "Ubuntu:25.10"
},
"versions": [
"1:22.2.0~dfsg+~cs6.15.60671435-2",
"1:22.3.0~dfsg+~cs6.15.60671435-1",
"1:22.4.1~dfsg+~cs6.15.60671435-1",
"1:22.4.1~dfsg+~cs6.15.60671435-2",
"1:22.5.1~dfsg+~cs6.15.60671435-1",
"1:22.5.2~dfsg+~cs6.15.60671435-1"
],
"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2021/UBUNTU-CVE-2021-26713.json"
},
"ecosystem_specific": {
"binaries": [
{
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"binary_version": "1:22.5.2~dfsg+~cs6.15.60671435-1"
},
{
"binary_name": "asterisk-config",
"binary_version": "1:22.5.2~dfsg+~cs6.15.60671435-1"
},
{
"binary_name": "asterisk-dahdi",
"binary_version": "1:22.5.2~dfsg+~cs6.15.60671435-1"
},
{
"binary_name": "asterisk-mobile",
"binary_version": "1:22.5.2~dfsg+~cs6.15.60671435-1"
},
{
"binary_name": "asterisk-modules",
"binary_version": "1:22.5.2~dfsg+~cs6.15.60671435-1"
},
{
"binary_name": "asterisk-mp3",
"binary_version": "1:22.5.2~dfsg+~cs6.15.60671435-1"
},
{
"binary_name": "asterisk-mysql",
"binary_version": "1:22.5.2~dfsg+~cs6.15.60671435-1"
},
{
"binary_name": "asterisk-ooh323",
"binary_version": "1:22.5.2~dfsg+~cs6.15.60671435-1"
},
{
"binary_name": "asterisk-tests",
"binary_version": "1:22.5.2~dfsg+~cs6.15.60671435-1"
}
]
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
}
]
}
],
"package": {
"name": "asterisk",
"purl": "pkg:deb/ubuntu/asterisk?arch=source&distro=stonking",
"ecosystem": "Ubuntu:26.10"
},
"versions": [
"1:22.5.2~dfsg+~cs6.15.60671435-1",
"1:22.10.0+dfsg+~cs6.17.60671434-1ubuntu2",
"1:22.10.0+dfsg+~cs6.17.60671434-1ubuntu3"
],
"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2021/UBUNTU-CVE-2021-26713.json"
},
"ecosystem_specific": {
"binaries": [
{
"binary_name": "asterisk",
"binary_version": "1:22.10.0+dfsg+~cs6.17.60671434-1ubuntu3"
},
{
"binary_name": "asterisk-config",
"binary_version": "1:22.10.0+dfsg+~cs6.17.60671434-1ubuntu3"
},
{
"binary_name": "asterisk-dahdi",
"binary_version": "1:22.10.0+dfsg+~cs6.17.60671434-1ubuntu3"
},
{
"binary_name": "asterisk-mobile",
"binary_version": "1:22.10.0+dfsg+~cs6.17.60671434-1ubuntu3"
},
{
"binary_name": "asterisk-modules",
"binary_version": "1:22.10.0+dfsg+~cs6.17.60671434-1ubuntu3"
},
{
"binary_name": "asterisk-mp3",
"binary_version": "1:22.10.0+dfsg+~cs6.17.60671434-1ubuntu3"
},
{
"binary_name": "asterisk-mysql",
"binary_version": "1:22.10.0+dfsg+~cs6.17.60671434-1ubuntu3"
},
{
"binary_name": "asterisk-ooh323",
"binary_version": "1:22.10.0+dfsg+~cs6.17.60671434-1ubuntu3"
},
{
"binary_name": "asterisk-tests",
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}
]
}
},
{
"ranges": [
{
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{
"introduced": "0"
}
]
}
],
"package": {
"name": "asterisk",
"purl": "pkg:deb/ubuntu/asterisk?arch=source&distro=resolute",
"ecosystem": "Ubuntu:26.04:LTS"
},
"versions": [
"1:22.5.2~dfsg+~cs6.15.60671435-1"
],
"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2021/UBUNTU-CVE-2021-26713.json"
},
"ecosystem_specific": {
"binaries": [
{
"binary_name": "asterisk",
"binary_version": "1:22.5.2~dfsg+~cs6.15.60671435-1"
},
{
"binary_name": "asterisk-config",
"binary_version": "1:22.5.2~dfsg+~cs6.15.60671435-1"
},
{
"binary_name": "asterisk-dahdi",
"binary_version": "1:22.5.2~dfsg+~cs6.15.60671435-1"
},
{
"binary_name": "asterisk-mobile",
"binary_version": "1:22.5.2~dfsg+~cs6.15.60671435-1"
},
{
"binary_name": "asterisk-modules",
"binary_version": "1:22.5.2~dfsg+~cs6.15.60671435-1"
},
{
"binary_name": "asterisk-mp3",
"binary_version": "1:22.5.2~dfsg+~cs6.15.60671435-1"
},
{
"binary_name": "asterisk-mysql",
"binary_version": "1:22.5.2~dfsg+~cs6.15.60671435-1"
},
{
"binary_name": "asterisk-ooh323",
"binary_version": "1:22.5.2~dfsg+~cs6.15.60671435-1"
},
{
"binary_name": "asterisk-tests",
"binary_version": "1:22.5.2~dfsg+~cs6.15.60671435-1"
}
]
}
}
],
"modified": "2026-10-17T12:57:12.003194728Z",
"provider": "osv",
"upstream": [
"CVE-2021-26713"
],
"references": [
"https://ubuntu.com/security/CVE-2021-26713",
"https://downloads.asterisk.org/pub/security/",
"https://downloads.asterisk.org/pub/security/AST-2021-004.html",
"https://issues.asterisk.org/jira/browse/ASTERISK-29205",
"https://www.cve.org/CVERecord?id=CVE-2021-26713"
]
},
"related_cves": [
{
"value": "CVE-2021-26713",
"evidence": "/upstream"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 356892,
"published_at": "2021-02-19T20:15:00+00:00"
}