CVE-2026-56416
Possible heap buffer overflow when validator canonicalizes RDATA that contains domain name
02 Description
Possible heap buffer overflow when validator canonicalizes RDATA that contains domain name
03 Exploitation and scoring
- Exploitation
- Assessed, none found. CISA's assessment recorded neither public exploit code nor evidence of exploitation when it was made.
- SSVC decision
- ExploitationnoneCISA recorded no public exploit code and no evidence of exploitation.
- AutomatablenoAt least one step from reconnaissance to exploitation cannot be reliably automated.
- Technical ImpactpartialSuccessful exploitation gives limited control of the vulnerable component.
- EPSS probability
- 0.12% probability of exploitation activity in the next 30 days.
- EPSS percentile
- Equal to or higher than the score of 1.9% of scored records. A rank, not a probability.
- NVD base score
- 4.8 (CVSS v3.x), scored by the NVD independently of the CNA.
- NVD CVSS vector
- CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:L
- NVD analysis status
- Analyzed. NVD last modified this record on 2026-10-24.
- Red Hat severity
- Moderate. Red Hat's rating for its own products, not a CVSS rating.
Exploit-prediction scores from FIRST. Independent scoring and analysis status from the NVD. Vendor severity from Red Hat. Exploitation assessment and catalog membership from CISA.
04 Metadata
- Published
- 2026-07-22 13:10Z3 MO AGO
- Last updated
- 2026-07-22 14:00Z3 MO AGO
- Reserved
- 2026-06-22
- Assigning CNA
- NLnet Labs
- Record state
- PUBLISHED
- Severity
- Medium (CVSS 4.8)
- CNA CVSS vector
- CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:L
- Weaknesses
- Data version
- 5.2
- Document digest
- bbbadb4b222dca2af393498ecc627cb16ff48992d82f334c2869754f2af21ad9
05 Affected products
06 References
- www.nlnetlabs.nlhttps://www.nlnetlabs.nl/downloads/unbound/CVE-2026-56416.txt
07 Remediation
This issue is fixed starting with version 1.25.2
08 Fixed in
Debian 12
- unbound No fix yet
Source: Debian Security Tracker, the Debian security team. Received through OSV.dev. Reformatted by exploit.cc.
Debian 13
- unbound Fixed in 1.26.1-0+deb13u1
Source: Debian Security Tracker, the Debian security team. Received through OSV.dev. Reformatted by exploit.cc.
Debian 14
- unbound Fixed in 1.25.2-1
Source: Debian Security Tracker, the Debian security team. Received through OSV.dev. Reformatted by exploit.cc.
Ubuntu 22.04 LTS
- unbound No fix yet
Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.
Ubuntu 24.04 LTS
- unbound No fix yet
Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.
Ubuntu 26.04 LTS
- unbound No fix yet
Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.
Ubuntu 26.10
- unbound No fix yet
Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.
Ubuntu Pro 14.04 LTS
- unbound No fix yet
Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.
Ubuntu Pro 16.04 LTS
- unbound No fix yet
Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.
Ubuntu Pro 18.04 LTS
- unbound No fix yet
Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.
Ubuntu Pro 20.04 LTS
- unbound No fix yet
Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.
A release or ecosystem missing from this list has no record here. It may be unaffected or not covered by the source. Source notices and licences.