CVE-2026-46406

Response disclosure and file overwrite via predictable path

Published Jun 29, 2026 · Updated Jun 29, 2026

Insecure temporary-file handling in Claude Code 2.1.59 through 2.1.127 allows local users to disclose responses or overwrite files. The /copy command writes response text to predictable /tmp/claude/response.md with mode 0644, without user isolation or protection against symbolic links. A low-privileged user on the same host must either read the generated file or plant a link before another user invokes /copy; exposed responses can contain secrets, while link following can replace an attacker-chosen file.

CVSS severity4.4
Medium
EPSS probability0.15%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Insecure temporary-file handling in Claude Code 2.1.59 through 2.1.127 allows local users to disclose responses or overwrite files. The /copy command writes response text to predictable /tmp/claude/response.md with mode 0644, without user isolation or protection against symbolic links. A low-privileged user on the same host must either read the generated file or plant a link before another user invokes /copy; exposed responses can contain secrets, while link following can replace an attacker-chosen file.

The record

CVE
CVE-2026-46406
Published
Jun 29, 2026
Updated
Jun 29, 2026
Vendor
Anthropic
Product
Claude Code
Classifications
CWE-59, CWE-377, CWE-200, T1005
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Jun 29, 2026CVE publishedPublication date reported by the CVE source.
  2. Jun 29, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

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

  1. Affected versionversion=>= 2.1.59, < 2.1.128

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

Anthropic · Claude Codeversion=>= 2.1.59, < 2.1.128

Published CVSS scores

6.1NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:L/I:L/A:H
4.4GitHub, Inc.CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:A/VC:L/VI:L/VA:H/SC:N/SI:N/SA: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)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-59Improper Link Resolution Before File Access ('Link Following')
CWE-377Insecure Temporary File
CWE-200Exposure of Sensitive Information to an Unauthorized Actor
T1005Data from Local System

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

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo