5.3

CVE-2026-5950: isc bind Unchecked Input for Loop Condition

CVSS: 5.3v3.1MediumAnalyzed
AliasesALPINE-CVE-2026-5950UBUNTU-CVE-2026-5950DEBIAN-CVE-2026-5950
Published 20-05-2026Last modified 20-05-2026
Open JSON

Vulnerability summary

CVE-2026-5950 is a medium (CVSS 5.3) Unchecked Input for Loop Condition vulnerability in isc bind. EPSS estimates a 0.80% chance of exploitation in the next 30 days, higher than 55.7% of scored vulnerabilities.

Overall risk
21/100
0100
Low · default modelHow is this calculated?
CVSS score
5.3/10
010
Medium · v3.1 (CVE.org)
EPSS score
0.80%
0%100%
Low · +0.14 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 7 · Related 6
MGASA-2026-0163OPENSUSE-SU-2026:10874-1OPENSUSE-SU-2026:21123-1RHSA-2026:20334SUSE-SU-2026:22198-1SUSE-SU-2026:2673-1

Timeline

  1. 20-05-2026
    PublishedVulnerability first disclosed.
  2. 20-05-2026
    Last modifiedVulnerability information updated.

Description

An unbounded resend loop vulnerability exists in the BIND 9 resolver state machine during bad-server handling, enabling a remote unauthenticated attacker to cause severe resource exhaustion by sending queries that trigger specific retry conditions. This issue affects BIND 9 versions 9.18.36 through 9.18.48, 9.20.8 through 9.20.22, 9.21.7 through 9.21.21, 9.18.36-S1 through 9.18.48-S1, and 9.20.9-S1 through 9.20.22-S1.

CVSS metrics

5 scores · 5 sources · 1 version

EPSS trend

Probability

0.80%

Chance of exploitation in the next 30 days

Percentile

56%

Versus all other CVEs

30-day change

+0.14 pp

From 0.66% on 19-09-2026

19-09-202619-10-2026
EPSS score
0.80%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Ubuntu3 products
  • bind9< 1:9.18.39-0ubuntu0.22.04.4 | < 1:9.18.39-0ubuntu0.24.04.5 | < 1:9.20.11-1ubuntu2.4 | < 1:9.20.18-1ubuntu2.1
  • bind9-libsAll versions (No fix recorded)
  • isc-dhcpAll versions (No fix recorded)
Isc2 products
  • bind≥ 9.18.36, < 9.18.49 | ≥ 9.20.8, < 9.20.23 | ≥ 9.21.7, < 9.21.21
  • bind 9≥ 9.18.36, ≤ 9.18.48 | ≥ 9.20.8, ≤ 9.20.22 | ≥ 9.21.7, ≤ 9.21.21 | ≥ 9.18.36-S1, ≤ 9.18.48-S1 | ≥ 9.20.9-S1, ≤ 9.20.22-S1
Alpine1 product
  • bind≥ 9.18.36, < 9.18.49-r0 | ≥ 9.18.36, < 9.20.23-r0
Debian1 product
  • bind9< 1:9.18.49-1~deb12u2 | < 1:9.20.23-1~deb13u1 | < 1:9.20.23-1

4 vendors · 7 products

References

10 links