CVE-2026-25723Network attack vector

Arbitrary file write via piped sed validation bypass

Published Feb 6, 2026 · Updated Feb 6, 2026

Command injection in Anthropic Claude Code before 2.0.55 allows remote attackers to write outside the project through piped shell commands. The command validator fails to recognize that an echo-to-sed pipeline can use sed file-writing behavior to bypass the approved write boundary. Exploitation requires command execution through Claude Code with accept edits enabled and permits writes to .claude and other out-of-project paths.

CVSS severity7.7
High
EPSS probability0.27%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Command injection in Anthropic Claude Code before 2.0.55 allows remote attackers to write outside the project through piped shell commands. The command validator fails to recognize that an echo-to-sed pipeline can use sed file-writing behavior to bypass the approved write boundary. Exploitation requires command execution through Claude Code with accept edits enabled and permits writes to .claude and other out-of-project paths.

The record

CVE
CVE-2026-25723
Published
Feb 6, 2026
Updated
Feb 6, 2026
Vendor
Anthropic
Product
Claude Code
Classifications
CWE-20, CWE-78, T1059.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Feb 6, 2026CVE publishedPublication date reported by the CVE source.
  2. Feb 6, 2026Record 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=< 2.0.55

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Anthropic · Claude Codeversion=< 2.0.55

Published CVSS scores

7.7GitHubCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
6.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N

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 exploitUnconfirmed

Weakness, pattern, technique

CWE-20Improper Input Validation
CWE-78Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')
T1059.004Unix Shell

Public exploit references

No public exploit references are available in this record.

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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