CVE-2023-2251Public exploitNetwork attack vector

Process crash via negative error-pointer repeat count

Published Apr 24, 2023 · Updated Feb 4, 2025

Uncaught exception in yaml 2.0.0-5 through 2.2.1 allows remote attackers to crash a consuming process via crafted YAML input. In prettifyError, an overlong carriage-return run makes the calculated caret length negative, and String.repeat throws a RangeError instead of returning a parse error. The default prettyErrors setting exposes the path when an application parses attacker-controlled YAML; the bounded consequence is failure of the current request or process, depending on host exception handling.

CVSS severity7.5
High
EPSS probability1.09%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Uncaught exception in yaml 2.0.0-5 through 2.2.1 allows remote attackers to crash a consuming process via crafted YAML input. In prettifyError, an overlong carriage-return run makes the calculated caret length negative, and String.repeat throws a RangeError instead of returning a parse error. The default prettyErrors setting exposes the path when an application parses attacker-controlled YAML; the bounded consequence is failure of the current request or process, depending on host exception handling.

The record

CVE
CVE-2023-2251
Published
Apr 24, 2023
Updated
Feb 4, 2025
Vendor
Eemeli Aro
Product
yaml
Classifications
CWE-248, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 24, 2023CVE publishedPublication date reported by the CVE source.
  2. Feb 4, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=unspecified <2.0.0-5

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Eemeli Aro · yamlversion=unspecified <2.0.0-5

Published CVSS scores

7.5huntr.devCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
7.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-248Uncaught Exception
T1499.004Application or System Exploitation

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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