CVE-2026-33599 | Out-of-bounds read in service discovery

A rogue backend can send a crafted SVCB response to a Discovery of Designated Resolvers request, when requested via either the autoUpgrade (Lua) option to newServer or auto_upgrade (YAML) settings. DDR upgrade is not enabled by default.

Published: 2026-04-22 Last update: 2026-04-24 Assigner: [email protected] Source: [email protected]
NVD Status：Analyzed，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2026-33599 is rated Low Risk (12.5/100): CVSS Low severity, with low exploitation likelihood (EPSS 0.01%). Low composite risk—no urgent action required; patch on your normal maintenance cycle and revisit priority if CVSS or EPSS increases.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2026-33599

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-04-23 — 0.01% —

Full EPSS history (1 record total)

Common vulnerability scoring system (CVSS) metrics for CVE-2026-33599

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
3.1 3.1 LOW
CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L Click to expand
Attack vector (AV:A)
Attacker has to be nearby on the network—same office, same link, that vibe—not the whole wide internet.
Attack complexity (AC:H)
Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:L)
Might cause slowdowns, glitches, or partial disruption—not a full brick.
 1.6 1.4 [email protected]
8.1 3.1 HIGH
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H Click to expand
Attack vector (AV:A)
Attacker has to be nearby on the network—same office, same link, that vibe—not the whole wide internet.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 2.8 5.2 [email protected]

Weakness enumeration for CVE-2026-33599

GitHub Security Advisory for CVE-2026-33599

GHSA-8fg9-fg58-x78h · Severity: low — A rogue backend can send a crafted SVCB response to a Discovery of Designated Resolvers request,...

OS Trackers for CVE-2026-33599

vendor priority summary link
debian end-of-life CVE-2026-33599 end-of-life priority: Debian including 1 source packages (dnsdist), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 3, open 2. https://security-tracker.debian.org/tracker/CVE-2026-33599
ubuntu medium CVE-2026-33599 medium priority: Ubuntu including 1 source packages (dnsdist), 8 status rows across 8 suites (bionic, focal, jammy, noble, questing, resolute, upstream, xenial): needs-triage 7, released 1. https://ubuntu.com/security/CVE-2026-33599

Affected software / configurations for CVE-2026-33599

Vendor Product Version Raw CPE
powerdns dnsdist >= 1.9.0, < 1.9.13 cpe:2.3:a:powerdns:dnsdist:*:*:*:*:*:*:*:*
powerdns dnsdist >= 2.0.0, < 2.0.4 cpe:2.3:a:powerdns:dnsdist:*:*:*:*:*:*:*:*

References for CVE-2026-33599

cvelogic Threat Intelligence