Claude Code Vulnerable to Command Injection via Piped sed Command Bypasses File Write Restrictions

published 2026-02-06 9 mo ago modified 2026-06-17 4 mo ago also EUVD-2026-5637 , GHSA-mhg7-666j-cqg4

cvss: 6.5; version 3.1, NVD
cisa kev: Not listed; not in CISA's catalog
epss: 0.4%; EPSS 0.4% chance of exploitation in 30 days, percentile 32%
public exploits: 0; none known

Claude Code is an agentic coding tool. Prior to version 2.0.55, Claude Code failed to properly validate commands using piped sed operations with the echo command, allowing attackers to bypass file write restrictions. This vulnerability enabled writing to sensitive directories like the .claude folder and paths outside the project scope. Exploiting this required the ability to execute commands through Claude Code with the "accept edits" feature enabled. This issue has been patched in version 2.0.55.

Patch / fix

fixed in 2

npm @anthropic-ai/claude-code 2.0.55
anthropic claude_code 2.0.55

CISA SSVC

Exploitation: none
Automatable: no
Technical impact: total
Assessed: 9 mo ago (2026-02-06)

Exploit prediction

0.39% chance of exploitation in the next 30 days, higher than 32% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CNA	4.0	7.7	CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
CNA	4.0	7.7	CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
NVD	3.1	6.5	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N

Affected packages

ecosystem	package	affected	fixed in
npm	@anthropic-ai/claude-code	<2.0.55	2.0.55

Affected products

anthropics claude-code

Classification

Weakness

CWE-20 Improper Input Validation
CWE-78 Improper Neutralization of Special Elements used in an OS Command

References

github.com /anthropics/claude-code/security/advisories/GHSA-mhg7-666j-cqg4
web, vendor-advisory
nvd.nist.gov /vuln/detail/CVE-2026-25723
advisory
github.com /anthropics/claude-code
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.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.

Summary