CVE-2026-13204: isc bind 9 Reachable Assertion
Vulnerability summary
CVE-2026-13204 is a high (CVSS 7.5) Reachable Assertion vulnerability in isc bind 9. EPSS estimates a 0.52% chance of exploitation in the next 30 days, higher than 43.1% of scored vulnerabilities.
Advisory lineage
Upstream 0 · Downstream 22 · Related 10Timeline
- 22-07-2026PublishedVulnerability first disclosed.
- 22-07-2026Last modifiedVulnerability information updated.
Description
If a provably insecure domain is covered by both an NSEC and NSEC3 record at the parent, and there exist an RRSIG for only one of these types, then BIND may exit unexpectedly with an assertion while validating this proof. This issue affects BIND 9 versions 9.11.0 through 9.18.50, 9.20.0 through 9.20.24, 9.21.0 through 9.21.23, 9.11.3-S1 through 9.18.50-S1, and 9.20.9-S1 through 9.20.24-S1.
CVSS metrics
5 scores · 5 sources · 1 version- OSV · AlpineEcosystem advisory · calculated7.5HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- OSV · UbuntuEcosystem advisory · calculated7.5HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- OSV · DebianEcosystem advisory · calculated7.5HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- NVDNIST7.5HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS trend
Probability
0.52%
Chance of exploitation in the next 30 days
Percentile
43%
Versus all other CVEs
30-day change
0.00 pp
From 0.52% on 19-09-2026
Known exploited
Compare KEV catalogsNot in any of the 3 tracked catalogs.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeAffected systems
Ubuntu3 products
- bind9All versions (No fix recorded) | < 1:9.9.5.dfsg-3ubuntu0.19+esm15 | < 1:9.10.3.dfsg.P4-8ubuntu1.19+esm11 | < 1:9.11.3+dfsg-1ubuntu1.19+esm6 | < 1:9.18.30-0ubuntu0.20.04.2+esm3 | < 1:9.18.39-0ubuntu0.22.04.6 | < 1:9.18.39-0ubuntu0.24.04.7 | < 1:9.20.24-1ubuntu0.3
- 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≥ 9.11.0, ≤ 9.18.50 | ≥ 9.20.0, ≤ 9.20.24 | ≥ 9.21.0, ≤ 9.21.23 | ≥ 9.11.3-S1, ≤ 9.18.50-S1 | ≥ 9.20.9-S1, ≤ 9.20.24-S1
Mageia1 product
- bind< 9.18.50-1.1.mga9
5 vendors · 7 products