CVE-2026-11721
published 2026-07-22CVE-2026-11721: It is possible for an attacker's zone to respond to a query with an RRSIG that has a smaller number of labels than the zone in which the RRSIG is contained…
PriorityP347high7.5CVSS 3.1
AVNACLPRNUINSUCNIHAN
EPSS
0.40%
32.8th percentile
It is possible for an attacker's zone to respond to a query with an RRSIG that has a smaller number of labels than the zone in which the RRSIG is contained. This causes `named` to produce a wildcard name for a zone that is shorter than the attacker's zone, which can result in cache poisoning. For this attack to have any effect, the resolver under attack must have set `synth-from-dnssec yes;` (which is the default).
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.
Affected
7 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| isc | bind | — | — |
| isc | bind_9 | 9.11.0 – 9.18.50 | — |
| isc | bind_9 | 9.11.3-S1 – 9.18.50-S1 | — |
| isc | bind_9 | 9.20.0 – 9.20.24 | — |
| isc | bind_9 | 9.20.9-S1 – 9.20.24-S1 | — |
| isc | bind_9 | 9.21.0 – 9.21.23 | — |
| ubuntu | bind9 | — | — |
CVSS provenance
nvdv3.17.5HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
vendor_redhat7.5HIGH
vendor_ubuntu6.8MEDIUM
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Ubuntu
Bind vulnerabilities
vendor_ubuntu·2026-08-19·CVSS 6.8
CVE-2026-11721 [MEDIUM] Bind vulnerabilities
Title: Bind vulnerabilities
Summary: Several security issues were fixed in Bind.
It was discovered that Bind incorrectly accepted NSEC3 records whose signer
name did not match the owning zone. A remote attacker could possibly use
this issue to perform NSEC3 impersonation attacks, bypassing DNSSEC
validation. (CVE-2026-10723)
It was discovered that Bind incorrectly handled Key Records using the
PRIVATEDNS algorithm. A remote attacker could possibly use this issue to
cause Bind to crash, resulting in a denial of service. (CVE-2026-10822)
It was discovered that Bind incorrectly handled wildcard CNAME expansion in
Response Policy Zones. A remote attacker could possibly use this issue to
bypass configured RPZ policies. (CVE-2026-11331)
It was discovered that Bind performed unnecessary vali
Red Hat
bind: bind9: Cache poisoning via label count discrepancy, RRSIG, wildcards
vendor_redhat·2026-07-22·CVSS 7.5
CVE-2026-11721 [HIGH] CWE-345 bind: bind9: Cache poisoning via label count discrepancy, RRSIG, wildcards
bind: bind9: Cache poisoning via label count discrepancy, RRSIG, wildcards
It is possible for an attacker's zone to respond to a query with an RRSIG that has a smaller number of labels than the zone in which the RRSIG is contained. This causes `named` to produce a wildcard name for a zone that is shorter than the attacker's zone, which can result in cache poisoning. For this attack to have any effect, the resolver under attack must have set `synth-from-dnssec yes;` (which is the default).
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.
It is possible for an attacker's zone to respond to a query with an RRSIG that has a smaller number of labels than the zone in which
GHSA
It is possible for an attacker's zone to respond to a query with an RRSIG that has a smaller number of labels than the zone in which the RRSIG is contained.
ghsa_unreviewed·2026-07-22
CVE-2026-11721 [HIGH] CWE-1284 It is possible for an attacker's zone to respond to a query with an RRSIG that has a smaller number of labels than the zone in which the RRSIG is contained.
It is possible for an attacker's zone to respond to a query with an RRSIG that has a smaller number of labels than the zone in which the RRSIG is contained. This causes `named` to produce a wildcard name for a zone that is shorter than the attacker's zone, which can result in cache poisoning. For this attack to have any effect, the resolver under attack must have set `synth-from-dnssec yes;` (which is the default).
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.
No detection rules found.
No public exploits indexed.
2026-07-22
Published