CVE-2026-39155
Knot DNS before 3.4.10 and 3.5.x before 3.5.4 contains a vulnerability in mod-onlinesign where...
Knot DNS before 3.4.10 and 3.5.x before 3.5.4 contains a vulnerability in mod-onlinesign where the next NSEC owner name can be computed incorrectly. This can create an overly broad authenticated denial interval, allowing downstream validating resolvers using aggressive negative caching to synthesize negative answers for legitimate names and causing resolver-side denial of service.
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
CVE List Score used
Knot DNS before 3.4.10 and 3.5.x before 3.5.4 contains a vulnerability in mod-onlinesign where the next NSEC owner name can be computed incorrectly. This can create an overly broad authenticated denial interval, allowing downstream validating resolvers using aggressive negative caching to synthesize negative answers for legitimate names and causing resolver-side denial of service.
- Record
CVE-2026-39155- 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-345
- Updated
- 2026-11-02
EUVDEUVD-2026-48433
Knot DNS before 3.4.10 and 3.5.x before 3.5.4 contains a vulnerability in mod-onlinesign where the next NSEC owner name can be computed incorrectly. This can create an overly broad authenticated denial interval, allowing downstream validating resolvers using aggressive negative caching to synthesize negative answers for legitimate names and causing resolver-side denial of service.
- Record
EUVD-2026-48433- 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
GitHub AdvisoriesGHSA-hxf3-75wr-4mhp
Knot DNS before 3.4.10 and 3.5.x before 3.5.4 contains a vulnerability in mod-onlinesign where...
Knot DNS before 3.4.10 and 3.5.x before 3.5.4 contains a vulnerability in mod-onlinesign where the next NSEC owner name can be computed incorrectly. This can create an overly broad authenticated denial interval, allowing downstream validating resolvers using aggressive negative caching to synthesize negative answers for legitimate names and causing resolver-side denial of service.
- Record
GHSA-hxf3-75wr-4mhp- 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-345
- Updated
- 2026-11-02
NVD
Knot DNS before 3.4.10 and 3.5.x before 3.5.4 contains a vulnerability in mod-onlinesign where the next NSEC owner name can be computed incorrectly. This can create an overly broad authenticated denial interval, allowing downstream validating resolvers using aggressive negative caching to synthesize negative answers for legitimate names and causing resolver-side denial of service.
- Record
CVE-2026-39155- 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-345
- Updated
- 2026-11-02
OSVDEBIAN-CVE-2026-39155
Knot DNS before 3.4.10 and 3.5.x before 3.5.4 contains a vulnerability in mod-onlinesign where the next NSEC owner name can be computed incorrectly. This can create an overly broad authenticated denial interval, allowing downstream validating resolvers using aggressive negative caching to synthesize negative answers for legitimate names and causing resolver-side denial of service.
- Record
DEBIAN-CVE-2026-39155- 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-2026-39155
Knot DNS before 3.4.10 and 3.5.x before 3.5.4 contains a vulnerability in mod-onlinesign where the next NSEC owner name can be computed incorrectly. This can create an overly broad authenticated denial interval, allowing downstream validating resolvers using aggressive negative caching to synthesize negative answers for legitimate names and causing resolver-side denial of service.
- Record
UBUNTU-CVE-2026-39155- 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 packages
| Package | Affected | Fixed |
|---|---|---|
knotDebian:12 |
All versions, plus listed versions 3.2.6-13.2.9-13.3.0-13.3.0-23.3.1-1 Show 41 moreShow less3.3.2-13.3.3-13.3.3-23.3.4-13.3.4-1.13.3.4-1.1~exp13.3.5-13.3.5-1.13.3.6-23.3.6-33.3.7-13.3.8-13.3.9-13.4.0-13.4.0-23.4.0-33.4.0-43.4.1-13.4.1-23.4.2-13.4.3-13.4.4-13.4.5-13.4.6-13.4.6-23.4.7-13.4.8-13.5.0-13.5.0-23.5.1-13.5.2-13.5.3-13.5.3-23.5.3-33.5.4-13.5.4-23.5.5-13.5.6-13.5.6-23.5.7-13.5.8-1 |
None known |
knotDebian:13 |
All versions, plus listed versions 3.4.6-23.4.7-13.4.8-13.5.0-13.5.0-2 Show 12 moreShow less3.5.1-13.5.2-13.5.3-13.5.3-23.5.3-33.5.4-13.5.4-23.5.5-13.5.6-13.5.6-23.5.7-13.5.8-1 |
None known |
knotDebian:14 |
before 3.5.4-1, plus listed versions 3.4.6-23.4.7-13.4.8-13.5.0-13.5.0-2 Show 5 moreShow less3.5.1-13.5.2-13.5.3-13.5.3-23.5.3-3 |
3.5.4-1 |
knotUbuntu:16.04:LTS |
All versions, plus listed versions 2.0.0-12.0.1-42.0.1-4build12.0.2-12.0.2-1build1 Show 6 moreShow less2.1.0~rc1-52-gd80ce77-12.1.0~rc1-55-gf227348-12.1.0-22.1.0-32.1.1-12.1.1-1build1 |
None known |
knotUbuntu:18.04:LTS |
All versions, plus listed versions 2.5.3-32.6.0-12.6.1-22.6.3-12.6.4-12.6.5-12.6.5-3 |
None known |
knotUbuntu:20.04:LTS |
All versions, plus listed versions 2.7.6-22.7.8-1 |
None known |
knotUbuntu:22.04:LTS |
All versions, plus listed versions 3.0.5-1ubuntu13.1.4-1ubuntu13.1.5-1ubuntu13.1.6-1ubuntu1 |
None known |
knotUbuntu:24.04:LTS |
All versions, plus listed versions 3.2.9-13.3.2-13.3.3-13.3.3-23.3.4-13.3.4-1.1build13.3.4-1.1build2 |
None known |
knotUbuntu:26.04:LTS |
All versions, plus listed versions 3.4.6-23.5.1-13.5.2-13.5.3-13.5.3-2 |
None known |
History
| Recorded | Changed | Sources |
|---|---|---|
| first indexed | CVE List, EUVD, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2026-39155 is a medium vulnerability (CVSS 6.5) in knot, published July 23, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.22%, the 12th percentile. Fixed in knot 3.5.4-1.