CVE-2021-31878
An issue was discovered in PJSIP in Asterisk before 16.19.1 and before 18.5.1. To exploit, a re...
An issue was discovered in PJSIP in Asterisk before 16.19.1 and before 18.5.1. To exploit, a re-INVITE without SDP must be received after Asterisk has sent a BYE request.
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
An issue was discovered in PJSIP in Asterisk before 16.19.1 and before 18.5.1. To exploit, a re-INVITE without SDP must be received after Asterisk has sent a BYE request.
- Record
CVE-2021-31878- 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 - CVSS 2.0
- 4.0 Medium
AV:N/AC:L/Au:S/C:N/I:N/A:P - Weakness
- CWE-617
- Updated
- 2026-11-02
CVE List No score
An issue was discovered in PJSIP in Asterisk before 16.19.1 and before 18.5.1. To exploit, a re-INVITE without SDP must be received after Asterisk has sent a BYE request.
- Record
CVE-2021-31878- Updated
- 2026-11-02
EUVDEUVD-2021-18753 No score
An issue was discovered in PJSIP in Asterisk before 16.19.1 and before 18.5.1. To exploit, a re-INVITE without SDP must be received after Asterisk has sent a BYE request.
- Record
EUVD-2021-18753- Updated
- 2026-11-03
GitHub AdvisoriesGHSA-h6p9-w9r4-7x73 No score
An issue was discovered in PJSIP in Asterisk before 16.19.1 and before 18.5.1. To exploit, a re...
An issue was discovered in PJSIP in Asterisk before 16.19.1 and before 18.5.1. To exploit, a re-INVITE without SDP must be received after Asterisk has sent a BYE request.
- Record
GHSA-h6p9-w9r4-7x73- Weakness
- CWE-617
- Updated
- 2026-11-02
OSV
An issue was discovered in PJSIP in Asterisk before 16.19.1 and before 18.5.1. To exploit, a re-INVITE without SDP must be received after Asterisk has sent a BYE request.
- Record
CVE-2021-31878- 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-2021-31878
An issue was discovered in PJSIP in Asterisk before 16.19.1 and before 18.5.1. To exploit, a re-INVITE without SDP must be received after Asterisk has sent a BYE request.
- Record
UBUNTU-CVE-2021-31878- 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 |
|---|---|---|
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 |
asteriskUbuntu:22.04:LTS |
All versions, plus listed versions 1:16.16.1~dfsg-21:16.16.1~dfsg-41:16.16.1~dfsg-4build11:16.16.1~dfsg+~2.10-11:18.10.0~dfsg+~cs6.10.40431411-2 |
None known |
asteriskUbuntu:24.04:LTS |
All versions, plus listed versions 1:20.4.0~dfsg+~cs6.13.40431414-21:20.5.0~dfsg+~cs6.13.40431414-11:20.5.1~dfsg+~cs6.13.40431414-11:20.5.2~dfsg+~cs6.13.40431414-11:20.6.0~dfsg+~cs6.13.40431414-1 Show 4 moreShow less1:20.6.0~dfsg+~cs6.13.40431414-21:20.6.0~dfsg+~cs6.13.40431414-2build31:20.6.0~dfsg+~cs6.13.40431414-2build41:20.6.0~dfsg+~cs6.13.40431414-2build5 |
None known |
asteriskUbuntu:25.10 |
All versions, plus listed versions 1:22.2.0~dfsg+~cs6.15.60671435-21:22.3.0~dfsg+~cs6.15.60671435-11:22.4.1~dfsg+~cs6.15.60671435-11:22.4.1~dfsg+~cs6.15.60671435-21:22.5.1~dfsg+~cs6.15.60671435-11:22.5.2~dfsg+~cs6.15.60671435-1 |
None known |
asteriskUbuntu:26.10 |
All versions, plus listed versions 1:22.5.2~dfsg+~cs6.15.60671435-11:22.10.0+dfsg+~cs6.17.60671434-1ubuntu21:22.10.0+dfsg+~cs6.17.60671434-1ubuntu3 |
None known |
asteriskUbuntu:26.04:LTS |
All versions, plus listed versions 1:22.5.2~dfsg+~cs6.15.60671435-1 |
None known |
History
| Recorded | Changed | Sources |
|---|---|---|
| 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-2021-31878 is a medium vulnerability (CVSS 6.5) in Digium Asterisk, published July 27, 2021. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 2.46%, the 84th percentile. No source names a fixed version.
References
seclists.org/fulldisclosure/2021/Jul/48
packetstormsecurity.com/files/163638/Asterisk-Project-Security-Advisory-AST-2021-007.html
downloads.asterisk.org/pub/security/AST-2021-007.html
issues.asterisk.org/jira/browse/ASTERISK-29381
downloads.digium.com/pub/security/AST-2021-007.html
nvd.nist.gov/vuln/detail/CVE-2021-31878
github.com/advisories/GHSA-h6p9-w9r4-7x73
ubuntu.com/security/CVE-2021-31878
cve.org/CVERecord?id=CVE-2021-31878