7.5

CVE-2026-11331: isc bind 9 Improper Filtering of Special Elements

CVSS: 7.5v3.1HighUndergoing analysis
AliasesALPINE-CVE-2026-11331UBUNTU-CVE-2026-11331DEBIAN-CVE-2026-11331
Published 22-07-2026Last modified 22-07-2026
Open JSON

Vulnerability summary

CVE-2026-11331 is a high (CVSS 7.5) Improper Filtering of Special Elements vulnerability in isc bind 9. EPSS estimates a 0.43% chance of exploitation in the next 30 days, higher than 35.6% of scored vulnerabilities.

Overall risk
30/100
0100
Medium · default modelHow is this calculated?
CVSS score
7.5/10
010
High · v3.1 (CVE.org)
EPSS score
0.43%
0%100%
Low · 0.00 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 20 · Related 10
MGASA-2026-0331OPENSUSE-SU-2026:11375-1OPENSUSE-SU-2026:21489-1RHSA-2026:54071RHSA-2026:54509RHSA-2026:54510

Timeline

  1. 22-07-2026
    PublishedVulnerability first disclosed.
  2. 22-07-2026
    Last modifiedVulnerability information updated.

Description

An attacker who knows (or guesses) that a resolver uses RPZ with wildcard CNAME policies can craft query names long enough to trigger a NAMETOOLONG error condition during RPZ processing. This is not handled correctly and may lead to defeating the RPZ rule. It also may lead to an unexpected exit of the BIND 9 software. This issue affects BIND 9 versions 9.16.0 through 9.18.50, 9.20.0 through 9.20.24, 9.21.0 through 9.21.23, 9.16.8-S1 through 9.18.50-S1, and 9.20.9-S1 through 9.20.24-S1.

CVSS metrics

5 scores · 5 sources · 1 version

EPSS trend

Probability

0.43%

Chance of exploitation in the next 30 days

Percentile

36%

Versus all other CVEs

30-day change

0.00 pp

From 0.43% on 19-09-2026

19-09-202619-10-2026
EPSS score
0.43%

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
  • bind9All versions (No fix recorded) | < 1:9.18.30-0ubuntu0.20.04.2+esm3 | < 1:9.18.39-0ubuntu0.22.04.5 | < 1:9.18.39-0ubuntu0.24.04.6 | < 1:9.20.24-1ubuntu0.2
  • bind9-libsAll versions (No fix recorded)
  • isc-dhcpAll versions (No fix recorded)
Alpine1 product
  • bind< 9.20.26-r0
Debian1 product
  • bind9< 1:9.18.49-1~deb12u2 | < 1:9.20.26-1~deb13u1 | < 1:9.20.26-1
Isc1 product
  • bind 9≥ 9.16.0, ≤ 9.18.50 | ≥ 9.20.0, ≤ 9.20.24 | ≥ 9.21.0, ≤ 9.21.23 | ≥ 9.16.8-S1, ≤ 9.18.50-S1 | ≥ 9.20.9-S1, ≤ 9.20.24-S1

4 vendors · 6 products

References

10 links