synced 8 MIN AGO
01 Record

CVE-2026-81634

Possible heap buffer overflow during DNSSEC canonicalization

HighPUBLISHEDCNA: NLnet Labs
CNA base score7.5 CVSS v3.xCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
View raw JSON

02 Description

Possible heap buffer overflow during DNSSEC canonicalization

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.
  • AutomatableyesAn attacker can reliably automate reconnaissance through exploitation, so this scales.
  • Technical ImpactpartialSuccessful exploitation gives limited control of the vulnerable component.
CISA publishes the decision points, not a final SSVC decision. The decision also depends on mission and well-being impact, which is a property of your deployment rather than of the vulnerability.
EPSS probability
0.48% probability of exploitation activity in the next 30 days.
EPSS percentile
Equal to or higher than the score of 41.0% of scored records. A rank, not a probability.
NVD base score
7.5 (CVSS v3.x), scored by the NVD independently of the CNA.
NVD CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD analysis status
Analyzed. NVD last modified this record on 2026-09-23.
Red Hat severity
Important. 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
2026-09-16 08:30Z1 MO AGO
Last updated
2026-09-16 14:32Z1 MO AGO
Reserved
2026-09-07
Assigning CNA
NLnet Labs
Record state
PUBLISHED
Severity
High (CVSS 7.5)
CNA CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Weaknesses
  • CWE-122Heap-based Buffer OverflowVariant
  • CWE-120Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')Base
Data version
5.2
Document digest
42338e19d675500e5fc9bbeee3f2f270e7154e742274ea7cdf5323992d8ce186

05 Affected products

VendorProductVersionsPlatforms
NLnet LabsUnbound0 to < 1.26.1—

06 References

07 Remediation

This issue is fixed starting with version 1.26.1

08 Fixed in

AlmaLinux 8

  • python3-unbound
    Fixed in 1.16.2-5.14.el8_10.4
  • unbound
    Fixed in 1.16.2-5.14.el8_10.4
  • unbound-devel
    Fixed in 1.16.2-5.14.el8_10.4
  • unbound-libs
    Fixed in 1.16.2-5.14.el8_10.4

Source: AlmaLinux, AlmaLinux OS. Copyright (c) 2023 AlmaLinux OS. Licensed under MIT License. Received through OSV.dev. Reformatted by exploit.cc.

AlmaLinux 9

  • python3-unbound
    Fixed in 1.24.2-3.el9_8.8
  • unbound
    Fixed in 1.24.2-3.el9_8.8
  • unbound-devel
    Fixed in 1.24.2-3.el9_8.8
  • unbound-dracut
    Fixed in 1.24.2-3.el9_8.8
  • unbound-libs
    Fixed in 1.24.2-3.el9_8.8

Source: AlmaLinux, AlmaLinux OS. Copyright (c) 2023 AlmaLinux OS. Licensed under MIT License. Received through OSV.dev. Reformatted by exploit.cc.

AlmaLinux 10

  • python3-unbound
    Fixed in 1.24.2-7.el10_2.6
  • unbound
    Fixed in 1.24.2-7.el10_2.6
  • unbound-anchor
    Fixed in 1.24.2-7.el10_2.6
  • unbound-devel
    Fixed in 1.24.2-7.el10_2.6
  • unbound-dracut
    Fixed in 1.24.2-7.el10_2.6
  • unbound-libs
    Fixed in 1.24.2-7.el10_2.6
  • unbound-utils
    Fixed in 1.24.2-7.el10_2.6

Source: AlmaLinux, AlmaLinux OS. Copyright (c) 2023 AlmaLinux OS. Licensed under MIT License. Received through OSV.dev. Reformatted by exploit.cc.

CloudLinux 8

  • python3-unbound
    Fixed in 1.16.2-5.14.el8_10.4
  • unbound
    Fixed in 1.16.2-5.14.el8_10.4
  • unbound-devel
    Fixed in 1.16.2-5.14.el8_10.4
  • unbound-libs
    Fixed in 1.16.2-5.14.el8_10.4

Derived from AlmaLinux 8. Partial coverage: only packages taken from AlmaLinux 8 are listed.

Source: CloudLinux errata, CloudLinux Inc. Derived from: AlmaLinux, AlmaLinux OS. Copyright (c) 2023 AlmaLinux OS. Licensed under MIT License. Received through OSV.dev. Reformatted by exploit.cc.

CloudLinux 9

  • python3-unbound
    Fixed in 1.24.2-3.el9_8.8
  • unbound
    Fixed in 1.24.2-3.el9_8.8
  • unbound-devel
    Fixed in 1.24.2-3.el9_8.8
  • unbound-dracut
    Fixed in 1.24.2-3.el9_8.8
  • unbound-libs
    Fixed in 1.24.2-3.el9_8.8

Derived from AlmaLinux 9. Partial coverage: only packages taken from AlmaLinux 9 are listed.

Source: CloudLinux errata, CloudLinux Inc. Derived from: AlmaLinux, AlmaLinux OS. Copyright (c) 2023 AlmaLinux OS. Licensed under MIT License. Received through OSV.dev. Reformatted by exploit.cc.

CloudLinux 10

  • python3-unbound
    Fixed in 1.24.2-7.el10_2.6
  • unbound
    Fixed in 1.24.2-7.el10_2.6
  • unbound-anchor
    Fixed in 1.24.2-7.el10_2.6
  • unbound-devel
    Fixed in 1.24.2-7.el10_2.6
  • unbound-dracut
    Fixed in 1.24.2-7.el10_2.6
  • unbound-libs
    Fixed in 1.24.2-7.el10_2.6
  • unbound-utils
    Fixed in 1.24.2-7.el10_2.6

Derived from AlmaLinux 10. Partial coverage: only packages taken from AlmaLinux 10 are listed.

Source: CloudLinux errata, CloudLinux Inc. Derived from: AlmaLinux, AlmaLinux OS. Copyright (c) 2023 AlmaLinux OS. Licensed under MIT License. Received through OSV.dev. Reformatted by exploit.cc.

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 1.26.1-1

Source: Debian Security Tracker, the Debian security team. Received through OSV.dev. Reformatted by exploit.cc.

Ubuntu 22.04 LTS

  • unbound
    Fixed in 1.13.1-1ubuntu5.17

Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.

Ubuntu 24.04 LTS

  • unbound
    Fixed in 1.19.2-1ubuntu3.12

Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.

Ubuntu 26.04 LTS

  • unbound
    Fixed in 1.24.2-1ubuntu2.4

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
    Fixed in 1.4.22-1ubuntu4.14.04.3+esm5
    Available with Ubuntu Pro with Legacy support add-on: https://ubuntu.com/pro

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
    Fixed in 1.5.8-1ubuntu1.1+esm5
    Available with Ubuntu Pro with Legacy support add-on: https://ubuntu.com/pro

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
    Fixed in 1.6.7-1ubuntu2.6+esm6
    Available with Ubuntu Pro (Infra-only): https://ubuntu.com/pro

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
    Fixed in 1.9.4-2ubuntu1.11+esm3
    Available with Ubuntu Pro (Infra-only): https://ubuntu.com/pro

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.