CVE-2021-46837
res_pjsip_t38 in Sangoma Asterisk 16.x before 16.16.2, 17.x before 17.9.3, and 18.x before 18.2.2...
res_pjsip_t38 in Sangoma Asterisk 16.x before 16.16.2, 17.x before 17.9.3, and 18.x before 18.2.2, and Certified Asterisk before 16.8-cert7, allows an attacker to trigger a crash by sending an m=image line and zero port in a response to a T.38 re-invite initiated by Asterisk. This is a re-occurrence of the CVE-2019-15297 symptoms but not for exactly the same reason. The crash occurs because there is an append operation relative to the active topology, but this should instead be a replace operation.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- Low
- User interaction
- None
What an attacker can affect
- Confidentiality
- None
- Integrity
- None
- Availability
- High
Exploit likelihood
What each source reports
NVD Score used
6.5
res_pjsip_t38 in Sangoma Asterisk 16.x before 16.16.2, 17.x before 17.9.3, and 18.x before 18.2.2, and Certified Asterisk before 16.8-cert7, allows an attacker to trigger a crash by sending an m=image line and zero port in a response to a T.38 re-invite initiated by Asterisk. This is a re-occurrence of the CVE-2019-15297 symptoms but not for exactly the same reason. The crash occurs because there is an append operation relative to the active topology, but this should instead be a replace operation.
- Record
CVE-2021-46837- CVSS 3.1
- 6.5 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H - Weakness
- CWE-476
- Updated
- 2026-11-02
CVE List No score
res_pjsip_t38 in Sangoma Asterisk 16.x before 16.16.2, 17.x before 17.9.3, and 18.x before 18.2.2, and Certified Asterisk before 16.8-cert7, allows an attacker to trigger a crash by sending an m=image line and zero port in a response to a T.38 re-invite initiated by Asterisk. This is a re-occurrence of the CVE-2019-15297 symptoms but not for exactly the same reason. The crash occurs because there is an append operation relative to the active topology, but this should instead be a replace operation.
- Record
CVE-2021-46837- Updated
- 2026-11-02
EUVDEUVD-2021-33492 No score
res_pjsip_t38 in Sangoma Asterisk 16.x before 16.16.2, 17.x before 17.9.3, and 18.x before 18.2.2, and Certified Asterisk before 16.8-cert7, allows an attacker to trigger a crash by sending an m=image line and zero port in a response to a T.38 re-invite initiated by Asterisk. This is a re-occurrence of the CVE-2019-15297 symptoms but not for exactly the same reason. The crash occurs because there is an append operation relative to the active topology, but this should instead be a replace operation.
- Record
EUVD-2021-33492- Updated
- 2026-11-03
GitHub AdvisoriesGHSA-544v-7w28-m77x
6.5
res_pjsip_t38 in Sangoma Asterisk 16.x before 16.16.2, 17.x before 17.9.3, and 18.x before 18.2.2...
res_pjsip_t38 in Sangoma Asterisk 16.x before 16.16.2, 17.x before 17.9.3, and 18.x before 18.2.2, and Certified Asterisk before 16.8-cert7, allows an attacker to trigger a crash by sending an m=image line and zero port in a response to a T.38 re-invite initiated by Asterisk. This is a re-occurrence of the CVE-2019-15297 symptoms but not for exactly the same reason. The crash occurs because there is an append operation relative to the active topology, but this should instead be a replace operation.
- Record
GHSA-544v-7w28-m77x- CVSS 3.1
- 6.5 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H - Weakness
- CWE-476
- Updated
- 2026-11-02
OSV
6.5
res_pjsip_t38 in Sangoma Asterisk 16.x before 16.16.2, 17.x before 17.9.3, and 18.x before 18.2.2, and Certified Asterisk before 16.8-cert7, allows an attacker to trigger a crash by sending an m=image line and zero port in a response to a T.38 re-invite initiated by Asterisk. This is a re-occurrence of the CVE-2019-15297 symptoms but not for exactly the same reason. The crash occurs because there is an append operation relative to the active topology, but this should instead be a replace operation.
- Record
CVE-2021-46837- CVSS 3.1
- 6.5 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H - Updated
- 2026-11-02
OSVDEBIAN-CVE-2021-46837
6.5
res_pjsip_t38 in Sangoma Asterisk 16.x before 16.16.2, 17.x before 17.9.3, and 18.x before 18.2.2, and Certified Asterisk before 16.8-cert7, allows an attacker to trigger a crash by sending an m=image line and zero port in a response to a T.38 re-invite initiated by Asterisk. This is a re-occurrence of the CVE-2019-15297 symptoms but not for exactly the same reason. The crash occurs because there is an append operation relative to the active topology, but this should instead be a replace operation.
- Record
DEBIAN-CVE-2021-46837- CVSS 3.1
- 6.5 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H - Updated
- 2026-11-02
OSVUBUNTU-CVE-2021-46837
6.5
res_pjsip_t38 in Sangoma Asterisk 16.x before 16.16.2, 17.x before 17.9.3, and 18.x before 18.2.2, and Certified Asterisk before 16.8-cert7, allows an attacker to trigger a crash by sending an m=image line and zero port in a response to a T.38 re-invite initiated by Asterisk. This is a re-occurrence of the CVE-2019-15297 symptoms but not for exactly the same reason. The crash occurs because there is an append operation relative to the active topology, but this should instead be a replace operation.
- Record
UBUNTU-CVE-2021-46837- CVSS 3.1
- 6.5 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H - Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
asteriskDebian:14 |
before 1:18.9.0~dfsg+~cs6.10.40431411-1, plus listed versions 0.1.11-30.1.11-3woody11:1.0.5-21:1.0.5-41:1.0.6-1 Show 45 moreShow less1:1.0.6-21:1.0.7-11:1.0.7.dfsg.1-11:1.0.7.dfsg.1-21:1.0.7.dfsg.1-2sarge11:1.0.7.dfsg.1-2sarge21:1.0.7.dfsg.1-2sarge31:1.0.7.dfsg.1-2sarge41:1.0.7.dfsg.1-2sarge51:1.0.7.dfsg.1-2sarge61:1.0.9.dfsg-11:1.0.9.dfsg-31:1.0.9.dfsg-41:1.0.9.dfsg-51:1.0.9.dfsg-61:1.2.0-beta1.dfsg-11:1.2.0-beta2.dfsg-11:1.2.0-beta2.dfsg-21:1.2.0-beta2.dfsg-31:1.2.0-rc1.dfsg-11:1.2.0-rc2.dfsg-11:1.2.0.dfsg-11:1.2.0.dfsg-21:1.2.0.dfsg-31:1.2.0.dfsg-41:1.2.0.dfsg-51:1.2.0.dfsg-61:1.2.1.dfsg-11:1.2.1.dfsg-21:1.2.1.dfsg-31:1.2.10.dfsg-11:1.2.10.dfsg-1bpo11:1.2.10.dfsg-21:1.2.10.dfsg-31:1.2.11.dfsg-11:1.2.12.1.dfsg-11:1.2.13~dfsg-11:1.2.13~dfsg-21:1.2.13~dfsg-2etch11:1.2.13~dfsg-2etch21:1.2.13~dfsg-2etch31:1.2.13~dfsg-2etch41:1.2.14~dfsg-11:1.2.14~dfsg-21:1.2.14~dfsg-3 |
1:18.9.0~dfsg+~cs6.10.40431411-1 |
asteriskDebian:10 From an advisory covering 20 CVEs |
before 1:16.28.0~dfsg-0+deb10u1, plus listed versions 1:16.10.0~dfsg-11:16.12.0~dfsg-11:16.15.0~dfsg-11:16.15.1~dfsg-11:16.16.1~dfsg+~2.10-1 Show 14 moreShow less1:16.16.1~dfsg+~2.10-21:16.16.1~dfsg-11:16.16.1~dfsg-1~bpo10+11:16.16.1~dfsg-21:16.16.1~dfsg-31:16.16.1~dfsg-41:16.2.1~dfsg-11:16.2.1~dfsg-1+deb10u11:16.2.1~dfsg-1+deb10u21:16.2.1~dfsg-21:16.23.0~dfsg+~2.10-11:16.23.0~dfsg+~cs6.10.20220309-11:16.23.0~dfsg+~cs6.10.20220309-21:16.23.0~dfsg+~cs6.10.40431411-1 |
1:16.28.0~dfsg-0+deb10u1 |
asteriskDebian:11 From an advisory covering 20 CVEs |
before 1:16.28.0~dfsg-0+deb11u1, plus listed versions 1:16.16.1~dfsg+~2.10-11:16.16.1~dfsg+~2.10-21:16.16.1~dfsg-11:16.16.1~dfsg-1+deb11u11:16.16.1~dfsg-1+deb11u1~bpo10+1 Show 7 moreShow less1:16.16.1~dfsg-21:16.16.1~dfsg-31:16.16.1~dfsg-41:16.23.0~dfsg+~2.10-11:16.23.0~dfsg+~cs6.10.20220309-11:16.23.0~dfsg+~cs6.10.20220309-21:16.23.0~dfsg+~cs6.10.40431411-1 |
1:16.28.0~dfsg-0+deb11u1 |
asteriskUbuntu:Pro:16.04:LTS |
All versions, plus listed versions 1:13.1.0~dfsg-1.1ubuntu31:13.1.0~dfsg-1.1ubuntu41:13.1.0~dfsg-1.1ubuntu4.11:13.1.0~dfsg-1.1ubuntu4.1+esm1 |
None known |
asteriskUbuntu:18.04:LTS |
All versions, plus listed versions 1:13.17.2~dfsg-1ubuntu11:13.17.2~dfsg-2ubuntu11:13.18.1~dfsg-1ubuntu11:13.18.3~dfsg-1ubuntu11:13.18.3~dfsg-1ubuntu21:13.18.3~dfsg-1ubuntu31:13.18.3~dfsg-1ubuntu4 |
None known |
asteriskUbuntu:20.04:LTS |
All versions, plus listed versions 1:16.2.1~dfsg-2build21:16.2.1~dfsg-2build31:16.2.1~dfsg-2ubuntu1 |
None known |
History
| Recorded | Changed | Sources |
|---|---|---|
| affected, facts | ||
| aliases | EUVD | |
| first indexed | CVE List, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2021-46837 is a medium vulnerability (CVSS 6.5) in Asterisk Certified Asterisk, published August 30, 2022. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 4.67%, the 91st percentile. Fixed in asterisk 1:18.9.0~dfsg+~cs6.10.40431411-1.
References
downloads.asterisk.org/pub/security/AST-2021-006.html
lists.debian.org/debian-lts-announce/2022/11/msg00021.html
debian.org/security/2022/dsa-5285
nvd.nist.gov/vuln/detail/CVE-2021-46837
github.com/advisories/GHSA-544v-7w28-m77x
security-tracker.debian.org/tracker/CVE-2021-46837
ubuntu.com/security/CVE-2021-46837
cve.org/CVERecord?id=CVE-2021-46837
Left out here: 197 versions. The JSON record has them.