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01 Record

CVE-2026-55973

'dns-error-reporting: yes' leads to stack buffer overflow

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
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02 Description

'dns-error-reporting: yes' leads to stack buffer overflow

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
0.28% probability of exploitation activity in the next 30 days.
EPSS percentile
Equal to or higher than the score of 20.3% 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 2026-10-24.
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
2026-07-22 13:09Z3 MO AGO
Last updated
2026-07-22 14:06Z3 MO AGO
Reserved
2026-06-22
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-20Improper Input ValidationClass
  • CWE-805Buffer Access with Incorrect Length ValueBase
Data version
5.2
Document digest
f55f7a795f695e964b5baa98e70688f5434fccc2013559a9d8fe60e915fd467a

05 Affected products

VendorProductVersionsPlatforms
NLnet LabsUnbound1.23.0 to < 1.25.2—

06 References

07 Remediation

This issue is fixed starting with version 1.25.2

08 Fixed in

AlmaLinux 9

  • python3-unbound
    Fixed in 1.24.2-3.el9_8.4
  • unbound
    Fixed in 1.24.2-3.el9_8.4
  • unbound-devel
    Fixed in 1.24.2-3.el9_8.4
  • unbound-dracut
    Fixed in 1.24.2-3.el9_8.4
  • unbound-libs
    Fixed in 1.24.2-3.el9_8.4

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_2.4
  • unbound
    Fixed in 1.24.2-7.el10_2.4
  • unbound-anchor
    Fixed in 1.24.2-7.el10_2.4
  • unbound-devel
    Fixed in 1.24.2-7.el10_2.4
  • unbound-dracut
    Fixed in 1.24.2-7.el10_2.4
  • unbound-libs
    Fixed in 1.24.2-7.el10_2.4
  • unbound-utils
    Fixed in 1.24.2-7.el10_2.4

Source: 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_8.4
  • unbound
    Fixed in 1.24.2-3.el9_8.4
  • unbound-devel
    Fixed in 1.24.2-3.el9_8.4
  • unbound-dracut
    Fixed in 1.24.2-3.el9_8.4
  • unbound-libs
    Fixed in 1.24.2-3.el9_8.4

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_2.4
  • unbound
    Fixed in 1.24.2-7.el10_2.4
  • unbound-anchor
    Fixed in 1.24.2-7.el10_2.4
  • unbound-devel
    Fixed in 1.24.2-7.el10_2.4
  • unbound-dracut
    Fixed in 1.24.2-7.el10_2.4
  • unbound-libs
    Fixed in 1.24.2-7.el10_2.4
  • unbound-utils
    Fixed in 1.24.2-7.el10_2.4

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 1.25.2-1

Source: Debian Security Tracker, the Debian security team. 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.

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.