PT-2026-34323 · Nlnet+1 · Unbound+1

Haruto Kimura · Published 2026-04-22 · Updated 2026-04-23 · CVE-2026-33259

Positive Technologies (AI Summary)

CVSS v3.1

5.0

Medium

Base vector

AV:N/AC:H/PR:H/UI:N/S:U/C:N/I:L/A:H

Name of the Vulnerable Software and Affected Versions Unbound (affected versions not specified)

Description Concurrent transfers of the same Response Policy Zone (RPZ) can result in inconsistent RPZ data, use after free (a memory corruption issue where a program continues to use a pointer after it has been freed), and/or a crash of the recursor. This scenario typically occurs when an RPZ provider is malfunctioning.

Recommendations At the moment, there is no information about a newer version that contains a fix for this vulnerability.

Use After Free

Weakness Enumeration

CWE-416

Related Identifiers

CVE-2026-33259

Affected Products

Powerdns Recursor

Unbound

References · 9

• https://cve.org/CVERecord?id=CVE-2026-33259 · Security Note
• https://osv.dev/vulnerability/DEBIAN-CVE-2026-33259 · Vendor Advisory
• https://docs.powerdns.com/recursor/security-advisories/powerdns-advisory-powerdns-2026-03.html · Vendor Advisory
• https://ubuntu.com/security/CVE-2026-33259 · Vendor Advisory
• https://osv.dev/vulnerability/UBUNTU-CVE-2026-33259 · Vendor Advisory
• https://nvd.nist.gov/vuln/detail/CVE-2026-33259 · Security Note
• https://security-tracker.debian.org/tracker/CVE-2026-33259 · Vendor Advisory
• https://twitter.com/CVEnew/status/2047012153862082839 · Twitter Post
• https://docs.powerdns.com/recursor/security-advisories/powerdns-advisory-2026-03.html#cve-2026-33259-concurrent-modification-of-rpz-data-can-lead-to-denial-of-service · Note