Bug 2506178
| Summary: | CVE-2026-40691 unbound: Unbound: Denial of Service via crafted DNSCrypt query [fedora-all] | ||
|---|---|---|---|
| Product: | [Fedora] Fedora | Reporter: | Marco Benatto <mbenatto> |
| Component: | unbound | Assignee: | Paul Wouters <paul.wouters> |
| Status: | CLOSED ERRATA | QA Contact: | Fedora Extras Quality Assurance <extras-qa> |
| Severity: | high | Docs Contact: | |
| Priority: | high | ||
| Version: | rawhide | CC: | dns-sig, minfrin, paul.wouters, pemensik, pj.pandit, tkorbar |
| Target Milestone: | --- | Keywords: | Security, SecurityTracking |
| Target Release: | --- | ||
| Hardware: | Unspecified | ||
| OS: | Unspecified | ||
| Whiteboard: | {"flaws": ["81123d51-1539-4276-bd43-46c11ce5c98b"]} | ||
| Fixed In Version: | unbound-1.25.2-1.fc44 unbound-1.25.2-1.fc43 | Doc Type: | --- |
| Doc Text: | Story Points: | --- | |
| Clone Of: | Environment: | ||
| Last Closed: | 2026-07-30 01:16:48 UTC | Type: | --- |
| Regression: | --- | Mount Type: | --- |
| Documentation: | --- | CRM: | |
| Verified Versions: | Category: | --- | |
| oVirt Team: | --- | RHEL 7.3 requirements from Atomic Host: | |
| Cloudforms Team: | --- | Target Upstream Version: | |
| Embargoed: | |||
| Bug Depends On: | |||
| Bug Blocks: | 2503062 | ||
FEDORA-2026-e495bd59ef (unbound-1.25.2-1.fc44) has been submitted as an update to Fedora 44. https://bodhi.fedoraproject.org/updates/FEDORA-2026-e495bd59ef FEDORA-2026-3170ee6a1c (unbound-1.25.2-1.fc43) has been submitted as an update to Fedora 43. https://bodhi.fedoraproject.org/updates/FEDORA-2026-3170ee6a1c FEDORA-2026-e495bd59ef has been pushed to the Fedora 44 testing repository. Soon you'll be able to install the update with the following command: `sudo dnf upgrade --enablerepo=updates-testing --refresh --advisory=FEDORA-2026-e495bd59ef` You can provide feedback for this update here: https://bodhi.fedoraproject.org/updates/FEDORA-2026-e495bd59ef See also https://fedoraproject.org/wiki/QA:Updates_Testing for more information on how to test updates. FEDORA-2026-3170ee6a1c has been pushed to the Fedora 43 testing repository. Soon you'll be able to install the update with the following command: `sudo dnf upgrade --enablerepo=updates-testing --refresh --advisory=FEDORA-2026-3170ee6a1c` You can provide feedback for this update here: https://bodhi.fedoraproject.org/updates/FEDORA-2026-3170ee6a1c See also https://fedoraproject.org/wiki/QA:Updates_Testing for more information on how to test updates. FEDORA-2026-e495bd59ef (unbound-1.25.2-1.fc44) has been pushed to the Fedora 44 stable repository. If problem still persists, please make note of it in this bug report. FEDORA-2026-3170ee6a1c (unbound-1.25.2-1.fc43) has been pushed to the Fedora 43 stable repository. If problem still persists, please make note of it in this bug report. |
Disclaimer: Community trackers are created by Red Hat Product Security team on a best effort basis. Package maintainers are required to ascertain if the flaw indeed affects their package, before starting the update process. A denial of service vulnerability has been discovered in Unbound when compiled with DNSCrypt support ('--enable-dnscrypt'). A single bad DNSCrypt query over TCP could underflow Unbound's DNSCrypt packet reading procedure that may lead to heap overflow and eventual server crash and denial of service. Unbound 1.25.2 includes fixes to select the proper buffer TCP buffer for DNSCrypt, to properly check against the buffer's capacity and to clear the buffer before writing the dnscrypt contents otherwise UDP queries can hit assertions.