CVE-2021-4235

Denial of service in gopkg.in/yaml.v2

MEDIUM

5.5

CVSS Score

Published: December 27, 2022 at 09:13 PM UTC

Updated: June 17, 2026 at 04:19 AM UTC

3 products affected across 3 vendorsYamlProject YamlYaml

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Severity

MEDIUM5.5

Exploit prediction

EPSS 0.4%

SSVC

PoC

Description

Due to unbounded alias chasing, a maliciously crafted YAML file can cause the system to consume significant system resources. If parsing user input, this may be used as a denial of service vector.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

Yaml · Yaml Projectgo

95%

v < 2.2.3

Affected range stops below 2.2.3, so it looks safe — our inference, not a vendor statement

Yaml · GitHub Com Go Yaml Yamlgo

60%

All versions

Project Yaml · Gopkg in Yaml V2go

60%

v < 2.2.3

Affected range stops below 2.2.3, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

Patch and advisory references

References (4)

PatchThird Party Advisory

Source: [email protected]

https://github.com/go-yaml/yaml/commit/bb4e33bf68bf89cad44d386192cbed201f35b241

ExploitPatchThird Party Advisory

Source: [email protected]

https://github.com/go-yaml/yaml/pull/375

Source: [email protected]

https://lists.debian.org/debian-lts-announce/2023/07/msg00001.html

Third Party Advisory

Source: [email protected]

https://pkg.go.dev/vuln/GO-2021-0061

SSVC — Action Prioritization

SSVCPoCNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

5.5MEDIUMCISA-ADP

Attack Vector: LOCAL
Complexity: LOW
Privileges: NONE
User Interaction: REQUIRED
Scope: UNCHANGED
Confidentiality: NONE
Integrity: NONE
Availability: HIGH

Vector?

Quick Info

StatusMODIFIED

CWE

NVD-CWE-noinfo

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