CVE-2026-11605: CWE-408 Incorrect Behavior Order - Early Amplification in ISC BIND 9
CVE-2026-11605 is a resource exhaustion vulnerability in ISC BIND 9 DNS server software related to DNSSEC validation. The issue arises because BIND 9 validates all RRSIG records in a DNS response, even when some are unnecessary. This can cause excessive CPU usage when querying authoritative servers that return many valid but superfluous RRSIG records. The vulnerability affects specific versions of BIND 9, including 9.20.0 through 9.20.24, 9.21.0 through 9.21.23, and 9.20.9-S1 through 9.20.24-S1. It has a high severity score of 7.5 but no known exploits in the wild. No official patch or remediation guidance is currently provided by the vendor.
AI Analysis
Technical Summary
CVE-2026-11605 is a high-severity resource exhaustion vulnerability in ISC BIND 9 DNS server software caused by inefficient DNSSEC validation behavior. BIND 9 always validates all RRSIG records in a DNS answer, regardless of necessity. This leads to disproportionate CPU consumption when a DNS query returns many valid but superfluous RRSIG records from an authoritative server or zone. The affected versions include 9.20.0 through 9.20.24, 9.21.0 through 9.21.23, and 9.20.9-S1 through 9.20.24-S1. The vulnerability does not impact confidentiality or integrity but can cause denial of service through resource exhaustion. There is no vendor advisory or patch available at this time, and no known exploits have been reported in the wild.
Potential Impact
The vulnerability can cause denial of service conditions by exhausting CPU resources on affected BIND 9 servers during DNSSEC validation of DNS responses containing many superfluous RRSIG records. This may degrade DNS server performance or availability. There is no impact on data confidentiality or integrity.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until an official fix is available, consider limiting exposure of affected BIND 9 servers to untrusted authoritative zones that may return excessive RRSIG records. Monitor server performance for unusual CPU usage related to DNSSEC validation.
CVE-2026-11605: CWE-408 Incorrect Behavior Order - Early Amplification in ISC BIND 9
Description
CVE-2026-11605 is a resource exhaustion vulnerability in ISC BIND 9 DNS server software related to DNSSEC validation. The issue arises because BIND 9 validates all RRSIG records in a DNS response, even when some are unnecessary. This can cause excessive CPU usage when querying authoritative servers that return many valid but superfluous RRSIG records. The vulnerability affects specific versions of BIND 9, including 9.20.0 through 9.20.24, 9.21.0 through 9.21.23, and 9.20.9-S1 through 9.20.24-S1. It has a high severity score of 7.5 but no known exploits in the wild. No official patch or remediation guidance is currently provided by the vendor.
CVSS v3.1
Score 7.5high
Affected software
pkg:github/isc/bind9Run on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
CVE-2026-11605 is a high-severity resource exhaustion vulnerability in ISC BIND 9 DNS server software caused by inefficient DNSSEC validation behavior. BIND 9 always validates all RRSIG records in a DNS answer, regardless of necessity. This leads to disproportionate CPU consumption when a DNS query returns many valid but superfluous RRSIG records from an authoritative server or zone. The affected versions include 9.20.0 through 9.20.24, 9.21.0 through 9.21.23, and 9.20.9-S1 through 9.20.24-S1. The vulnerability does not impact confidentiality or integrity but can cause denial of service through resource exhaustion. There is no vendor advisory or patch available at this time, and no known exploits have been reported in the wild.
Potential Impact
The vulnerability can cause denial of service conditions by exhausting CPU resources on affected BIND 9 servers during DNSSEC validation of DNS responses containing many superfluous RRSIG records. This may degrade DNS server performance or availability. There is no impact on data confidentiality or integrity.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until an official fix is available, consider limiting exposure of affected BIND 9 servers to untrusted authoritative zones that may return excessive RRSIG records. Monitor server performance for unusual CPU usage related to DNSSEC validation.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- isc
- Date Reserved
- 2026-06-08T15:26:55.139Z
- Cvss Version
- 3.1
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 6a60d93c9c2644c7f83639f9
Added to database: 07/22/2026, 14:52:44 UTC
Last enriched: 07/22/2026, 15:08:09 UTC
Last updated: 07/22/2026, 16:52:28 UTC
Views: 3
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