CVE-2026-42387
Insufficient input validation in ZoneToCache
CVE-2026-42387 is a medium vulnerability (CVSS 5.9) in Powerdns Recursor, published June 25, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.48%, the 41st percentile. Fixed in pdns-recursor 5.4.3-r0.
A malicious authoritative server can send a crafted zone via the ZoneToCache function that leads to a crash of the Recursor due to insuffcient input validation.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- High
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- None
- Integrity
- None
- Availability
- High
Exploit likelihood
What each source reports
CVE List Score used
Insufficient input validation in ZoneToCache
A malicious authoritative server can send a crafted zone via the ZoneToCache function that leads to a crash of the Recursor due to insuffcient input validation.
- Record
CVE-2026-42387- CVSS 3.1
- 5.9 Medium
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H - Weakness
- CWE-20
- Updated
- 2026-11-02
EUVDEUVD-2026-39357
A malicious authoritative server can send a crafted zone via the ZoneToCache function that leads to a crash of the Recursor due to insuffcient input validation.
- Record
EUVD-2026-39357- CVSS 3.1
- 5.9 Medium
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-9v36-5rhx-cq6m
A malicious authoritative server can send a crafted zone via the ZoneToCache function that leads...
A malicious authoritative server can send a crafted zone via the ZoneToCache function that leads to a crash of the Recursor due to insuffcient input validation.
- Record
GHSA-9v36-5rhx-cq6m- CVSS 3.1
- 5.9 Medium
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H - Weakness
- CWE-20
- Updated
- 2026-11-02
NVD
A malicious authoritative server can send a crafted zone via the ZoneToCache function that leads to a crash of the Recursor due to insuffcient input validation.
- Record
CVE-2026-42387- CVSS 3.1
- 5.9 Medium
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H - Weakness
- CWE-20
- Updated
- 2026-11-02
OSVALPINE-CVE-2026-42387
A malicious authoritative server can send a crafted zone via the ZoneToCache function that leads to a crash of the Recursor due to insuffcient input validation.
- Record
ALPINE-CVE-2026-42387- CVSS 3.1
- 5.9 Medium
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H - Updated
- 2026-11-03
OSV
Insufficient input validation in ZoneToCache
A malicious authoritative server can send a crafted zone via the ZoneToCache function that leads to a crash of the Recursor due to insuffcient input validation.
- Record
CVE-2026-42387- CVSS 3.1
- 5.9 Medium
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H - Updated
- 2026-11-02
OSVDEBIAN-CVE-2026-42387
A malicious authoritative server can send a crafted zone via the ZoneToCache function that leads to a crash of the Recursor due to insuffcient input validation.
- Record
DEBIAN-CVE-2026-42387- CVSS 3.1
- 5.9 Medium
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H - Updated
- 2026-11-02
OSVUBUNTU-CVE-2026-42387
A malicious authoritative server can send a crafted zone via the ZoneToCache function that leads to a crash of the Recursor due to insuffcient input validation.
- Record
UBUNTU-CVE-2026-42387- CVSS 3.1
- 5.9 Medium
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H - Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
pdns-recursorAlpine:v3.24 |
before 5.4.3-r0 | 5.4.3-r0 |
pdns-recursorDebian:12 |
All versions, plus listed versions 4.8.4-14.8.6-14.8.7-14.8.8-14.8.8-1+deb12u1 Show 45 moreShow less4.9.0-14.9.0-24.9.1-14.9.1-24.9.1-34.9.1-44.9.2-14.9.2-24.9.3-14.9.4-14.9.5-15.0.5-15.0.7-15.0.7-25.0.9-15.1.3-15.1.3-25.2.0-15.2.0-25.2.0-35.2.0-45.2.0-55.2.1-15.2.2-15.2.2-25.2.4-15.2.4-25.2.5-15.3.0-15.3.0-25.3.0-35.3.0-45.3.0-55.3.1-15.3.3-15.3.4-15.3.4-25.3.5-15.4.0-15.4.1-15.4.1-25.4.2-15.4.2-25.4.3-15.4.4-1 |
None known |
pdns-recursorDebian:13 |
before 5.2.11-0+deb13u1, plus listed versions 5.2.4-25.2.4-2+deb13u15.2.5-15.2.6-0+deb13u15.2.7-0+deb13u15.2.8-0+deb13u15.2.9-0+deb13u1 |
5.2.11-0+deb13u1 |
pdns-recursorDebian:14 |
before 5.4.3-1, plus listed versions 5.2.4-25.2.5-15.3.0-15.3.0-25.3.0-3 Show 12 moreShow less5.3.0-45.3.0-55.3.1-15.3.3-15.3.4-15.3.4-25.3.5-15.4.0-15.4.1-15.4.1-25.4.2-15.4.2-2 |
5.4.3-1 |
pdns-recursorUbuntu:Pro:16.04:LTS |
All versions, plus listed versions 3.7.3-14.0.0~alpha1-14.0.0~alpha1-24.0.0~alpha2-24.0.0~alpha2-2ubuntu0.14.0.0~alpha2-2ubuntu0.1+esm1 |
None known |
pdns-recursorUbuntu:Pro:18.04:LTS |
All versions, plus listed versions 4.0.6-14.0.6-1build14.0.7-14.1.1-14.1.1-1build14.1.1-24.1.1-2ubuntu0.1~esm1 |
None known |
pdns-recursorUbuntu:Pro:20.04:LTS |
All versions, plus listed versions 4.2.0-64.2.1-14.2.1-1build14.2.1-1build24.2.1-1ubuntu0.1~esm1 |
None known |
pdns-recursorUbuntu:Pro:22.04:LTS |
All versions, plus listed versions 4.4.2-34.6.0-1ubuntu14.6.0-1ubuntu1+esm1 |
None known |
pdns-recursorUbuntu:24.04:LTS |
All versions, plus listed versions 4.9.0-24.9.1-44.9.2-14.9.2-1build14.9.2-24.9.3-14.9.3-1build24.9.3-1build3 |
None known |
pdns-recursorUbuntu:25.10 |
All versions, plus listed versions 5.2.0-55.2.2-15.2.2-25.2.4-25.2.4-2build2 |
None known |
pdns-recursorUbuntu:26.10 |
All versions, plus listed versions 5.3.5-15.4.3-15.4.5-1 |
None known |
pdns-recursorUbuntu:26.04:LTS |
All versions, plus listed versions 5.2.4-2build25.3.1-15.3.3-15.3.4-15.3.4-1build15.3.4-25.3.5-1 |
None known |
History
| When | Changed | Sources |
|---|---|---|
| 2026-11-03 | affected, aliases, references | OSV |
| 2026-11-02 | created | CVE List, EUVD, GitHub Advisories, NVD, OSV |
References
docs.powerdns.com/recursor/security-advisories/powerdns-advisory-powerdns-2026-08.html
nvd.nist.gov/vuln/detail/CVE-2026-42387
github.com/advisories/GHSA-9v36-5rhx-cq6m
security.alpinelinux.org/vuln/CVE-2026-42387
repo.powerdns.com
Left out here: 4 versions. The JSON record has them.