CVE-2026-5950
Unbounded resend loop in BIND 9 resolver
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.
- 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
- Data version
- 5.2
- Document digest
- 6a8c6311afdf53a5aea3c9f107db787c8710c009dc1b80c7fd7d4bc507d3426b
05 Affected products
06 References
- kb.isc.orgCVE-2026-5950https://kb.isc.org/docs/cve-2026-5950
- downloads.isc.orghttps://downloads.isc.org/isc/bind9/9.18.49
- downloads.isc.orghttps://downloads.isc.org/isc/bind9/9.20.23
- downloads.isc.orghttps://downloads.isc.org/isc/bind9/9.21.22
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.