CVE-2026-77955 Affecting libunbound8 package, versions <1.26.1-150100.10.31.1


Severity

Recommended
0.0
medium
0
10

Based on SUSE Linux Enterprise Server security rating.

Threat Intelligence

EPSS
0.17% (6th percentile)

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  • Snyk IDSNYK-SLES155-LIBUNBOUND8-20876373
  • published13 Oct 2026
  • disclosed12 Oct 2026

Introduced: 12 Oct 2026

NewCVE-2026-77955  (opens in a new tab)

How to fix?

Upgrade SLES:15.5 libunbound8 to version 1.26.1-150100.10.31.1 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream libunbound8 package and not the libunbound8 package as distributed by SLES. See How to fix? for SLES:15.5 relevant fixed versions and status.

In NLnet Labs Unbound 1.13.2 up to and including 1.26.1, a vulnerability in ZONEMD configured zones (zonemd-check: yes) which are located below (but not at) a trust anchor allow for an attack window where (tampered with) zone contents are served (or stored to disk) prior to the ZONEMD integrity check. This is caused by the needed DS/DNSKEY asynchronous resolution that needs to happen before the ZONEMD check completes. If a zonefile is written to disk (zonefile: option) while the ZONEMD check failed, the tampered data are reloaded on startup and available until ZONEMD verification concludes again. If verification fails, the data is not served any more but still persists on disk for future reloads.

CVSS Base Scores

version 3.1