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9.1 Critical

CVE-2026-33278 NLnet Labs Unbound 1.19.1 up to and including version 1.25.0 has a vulnerability in the DNSSEC validator that enables…

Description

NLnet Labs Unbound 1.19.1 up to and including version 1.25.0 has a vulnerability in the DNSSEC validator that enables denial of service and possible remote code execution as a result of deep copying a data structure and erroneously overwriting a destination pointer. An adversary can exploit the vulnerability by controlling a malicious signed zone and querying a vulnerable Unbound. When DS sub-queries need to suspend validation due to NSEC3 computational budget exhaustion (introduced in Unbound 1.19.1), Unbound deep-copies response messages to preserve them across memory region teardown. A struct-assignment bug overwrites the destination's pointer with the source's pointer. After the sub-query region is freed, the resumed validator dereferences this dangling pointer, triggering a crash or potentially enabling arbitrary code execution. Unbound 1.25.1 contains a patch with a fix to preserve the correct pointer when deep copying the data structure.

Affected products and versions

Product Affected versions Fixed in
unbound 1.19 1.19.1 → < 1.25.1 1.25.1
Red Hat Enterprise Linux AppStream (v. 10) Versions not published
Red Hat Enterprise Linux AppStream (v. 9) Versions not published
Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) Versions not published
Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) Versions not published
Red Hat Hardened Images 1.25 earliest → < 1.25.1-0.1.hum1 1.25.1-0.1.hum1
Red Hat Enterprise Linux 6 Versions not published
Red Hat OpenShift Container Platform 4 Versions not published
Red Hat Enterprise Linux 7 Versions not published
Show the 3 other branches
Product Affected versions Fixed in
Red Hat Enterprise Linux 8 Versions not published
Red Hat Enterprise Linux 10 Versions not published
Red Hat Enterprise Linux 9 Versions not published

References

Timeline

  1. Published
  2. Last modified

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