CVE-2026-40691
CVE-2026-40691: 1 tracked advisory record across Red Hat. Compare source-reported impact, fixes and remediation.
Compare the source-linked records below. Ratings and product/version details belong to each advisory; they are not a single CVE-wide score or proof that every listed product is affected. How VulniPulse collects and checks evidence.
Vendor advisory comparison
Red Hat
1 advisory- Advisory severityHigh7.5
High [CVE-2026-40691] Denial of Service via crafted DNSCrypt query
CVE-2026-40691Source published Source updated
In Unbound 1.9.0 up to and including 1.25.1, when a DNSCrypt query is received over TCP, the routine that encrypts the reply in place fails to bound the reply length against the destination buffer size. The size clamp that protects the UDP path is not applied on the TCP path, so a reply larger than 65504 bytes is shifted forward by 48 bytes inside a buffer of capacity equal to 'msg-buffer-size', writing past the end of the heap allocation. A single malicious encrypted query crashes the resolver and lead to denial of service. This vulnerability needs Unbound to be compiled with DNSCrypt support ('--enable-dnscrypt') and the 'dnscrypt:' clause to be configured and enabled for the listening interfaces. A flaw was found in Unbound, a domain name system (DNS) resolver. When Unbound is…
- Affected products in this advisory
- Red Hat Hardened Images
- Source-reported affected versions
- 1.9.0
- 1.25.1
- Source-reported fixed versions
- unbound-main-1.25.2-0.1.hum1
- RHSA-2026:43588
- Mitigation guidance
- No mitigation guidance extracted; consult the source.
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