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01 Record

CVE-2026-5950

Unbounded resend loop in BIND 9 resolver

MediumPUBLISHEDCNA: isc
CNA base score5.3 CVSS v3.xCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

02 Description

Unbounded resend loop in BIND 9 resolver

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
0.66% probability of exploitation activity in the next 30 days.
EPSS percentile
Equal to or higher than the score of 51.2% of scored records. A rank, not a probability.
NVD base score
5.3 (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:L
NVD analysis status
Analyzed. NVD last modified this record on 2026-07-23.
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
2026-05-20 13:10Z5 MO AGO
Last updated
2026-05-20 13:38Z5 MO AGO
Reserved
2026-04-09
Assigning CNA
isc
Record state
PUBLISHED
Severity
Medium (CVSS 5.3)
CNA CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Weaknesses
  • CWE-606Unchecked Input for Loop ConditionBase
  • CWE-835Loop with Unreachable Exit Condition ('Infinite Loop')Base
Data version
5.2
Document digest
6a8c6311afdf53a5aea3c9f107db787c8710c009dc1b80c7fd7d4bc507d3426b

05 Affected products

VendorProductVersionsPlatforms
ISCBIND 99.18.36 to 9.18.48, 9.20.8 to 9.20.22, 9.21.7 to 9.21.21, 9.18.36-S1 to 9.18.48-S1, 9.20.9-S1 to 9.20.22-S1—

06 References

07 Remediation

Upgrade to the patched release most closely related to your current version of BIND 9: 9.18.49, 9.20.23, 9.21.22, 9.18.49-S1, or 9.20.23-S1.

08 Fixed in

Debian 12

  • bind9
    Fixed in 1:9.18.49-1~deb12u2

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

Debian 13

  • bind9
    Fixed in 1:9.20.23-1~deb13u1

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

Debian 14

  • bind9
    Fixed in 1:9.20.23-1

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

Ubuntu 18.04 LTS

  • isc-dhcp
    No fix yet

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

Ubuntu 20.04 LTS

  • bind9-libs
    No fix yet

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

Ubuntu 22.04 LTS

  • bind9
    Fixed in 1:9.18.39-0ubuntu0.22.04.4
  • bind9-libs
    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

  • bind9
    Fixed in 1:9.18.39-0ubuntu0.24.04.5
  • isc-dhcp
    No fix yet

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

Ubuntu 25.10

  • bind9
    Fixed in 1:9.20.11-1ubuntu2.4
  • isc-dhcp
    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

  • bind9
    Fixed in 1:9.20.18-1ubuntu2.1
  • isc-dhcp
    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.