CVE-2026-33320 | Dasel has unbounded YAML alias expansion in dasel leads to CPU/memory denial of service

Exp

Dasel is a command-line tool and library for querying, modifying, and transforming data structures. Starting in version 3.0.0 and prior to version 3.3.1, Dasel's YAML reader allows an attacker who can supply YAML for processing to trigger extreme CPU and memory consumption. The issue is in the library's own `UnmarshalYAML` implementation, which manually resolves alias nodes by recursively following `yaml.Node.Alias` pointers without any expansion budget, bypassing go-yaml v4's built-in alias expansion limit. Version 3.3.2 contains a patch for the issue.

Published: 2026-03-23 Last update: 2026-06-17 Assigner: [email protected] Source: [email protected]
NVD Status：Analyzed，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2026-33320 is rated Exploit Available (50/100): CVSS Medium severity, with low exploitation likelihood (EPSS 0.21%). 1 public exploit reference(s) are indexed (Exploit-DB). Public exploits are available—assess exposure, apply mitigations, and prioritize patching.

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

Public exploit references (Exploit-DB) for CVE-2026-33320

EDB-ID Source Kind Published Link
— nvd_ref exploit_tag Exploit-DB ↗

Exploit prediction scoring system (EPSS) score for CVE-2026-33320

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 2026-06-15 0.01% 0.21% +0.20%
2 2026-03-24 — 0.01% —

Full EPSS history (2 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2026-33320

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
6.2 3.1 MEDIUM
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Click to expand
Attack vector (AV:L)
They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by.
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:N)
Doesn’t really leak secrets in a meaningful 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.
 2.5 3.6 [email protected]

Weakness enumeration for CVE-2026-33320

GitHub Security Advisory for CVE-2026-33320

GHSA-4fcp-jxh7-23x8 · Severity: medium · Ecosystem: go — Dasel has unbounded YAML alias expansion in dasel leads to CPU/memory denial of service

OS Trackers for CVE-2026-33320

vendor priority summary link
debian unimportant CVE-2026-33320 unimportant priority: Debian including 1 source packages (dasel), 3 status rows across 3 suites (forky, sid, trixie): resolved 3. https://security-tracker.debian.org/tracker/CVE-2026-33320
ubuntu medium CVE-2026-33320 medium priority: Ubuntu including 1 source packages (dasel), 4 status rows across 4 suites (jammy, noble, questing, upstream): needs-triage 2, DNE 1, not-affected 1. https://ubuntu.com/security/CVE-2026-33320

Affected software / configurations for CVE-2026-33320

Vendor Product Version Raw CPE
tomwright dasel >= 3.0.0, < 3.3.2 cpe:2.3:a:tomwright:dasel:*:*:*:*:*:go:*:*

References for CVE-2026-33320

cvelogic Threat Intelligence