Dasel has unbounded YAML alias expansion in dasel leads to CPU/memory denial of service

published 2026-03-19 7 mo ago modified 2026-09-10 1 mo ago also GHSA-4fcp-jxh7-23x8 , GO-2026-4768 , EUVD-2026-20094

cvss: 6.2; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.2%; EPSS 0.2% chance of exploitation in 30 days, percentile 12%
public exploits: 0; none known

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.

Patch / fix

fixed in 2 distros 2

go github.com/tomwright/dasel/v3 3.3.2
tomwright dasel 3.3.2

suse opensuse

govulncheck-vulndb openSUSE Leap 15.6 0.0.20260326T203309-150000.1.155.2

suse advisories SUSE-SU-2026:1135-1

govulncheck-vulndb openSUSE Leap 16.0 0.0.20260723T184607-160000.1.1

opensuse advisories openSUSE-SU-2026:21483-1

CISA SSVC

Exploitation: Proof of concept is public
Automatable: no
Technical impact: partial
Assessed: 7 mo ago (2026-03-26)

Exploit prediction

0.22% chance of exploitation in the next 30 days, higher than 12% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

github.com https://github.com/TomWright/dasel/security/advisories/GHSA-4fcp-jxh7-23x8 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by	version	score	vector
CNA	3.1	6.2	CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
GitHub	3.1	6.2	CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected packages

ecosystem	package	affected	fixed in
go	github.com/tomwright/dasel/v3	>=3.0.0, <3.3.2	3.3.2
go	github.com/tomwright/dasel	all versions	no fix listed
go	github.com/tomwright/dasel/v2	all versions	no fix listed

Affected products

TomWright dasel

Classification

Weakness

CWE-674 Uncontrolled Recursion

References

github.com /TomWright/dasel/security/advisories/GHSA-4fcp-jxh7-23x8
web, exploit, mitigation, vendor-advisory, advisory
nvd.nist.gov /vuln/detail/CVE-2026-33320
advisory
github.com /TomWright/dasel
package

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary