HighGHSA-5j29-h97v-84chCVE-2026-1034355 Oct · 18 days ago
Source ↗

Arbitrary File Write via Write-Time Symlink Following (TOCTOU) in Claude Code.

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Claude Code validated that a target file path resided within the project working directory at permission-check time, but re-resolved the path at write time without repeating that validation. This time-of-check to time-of-use (TOCTOU) gap allowed an attacker who could write to the workspace to atomically replace a project file with a symlink, causing Claude Code to follow the symlink and write its output to an arbitrary file outside the project sandbox. Exploitation required the ability to win a race condition against the write operation and write access to the shared workspace, enabling a lowe

SourcesGitHub advisory

Timeline

5 Oct
18 daysfrom publication to Patchwire
  1. Published by GitHub advisory5 Oct
  2. Seen by Patchwire23 Oct
  3. Fix released5 Oct
@anthropic-ai/claude-code2.1.129

Versions of @anthropic-ai/claude-code

2.x
safe 2.1.129
AffectedSafe

Packages

@anthropic-ai/claude-code

Stacks

Claude Code

Related alerts(2)

Same packages

Claude Code: Plugin Hash Pin Bypass Allows Bypass of Hash Pinning

@anthropic-ai/claude-code · 9 Oct

High
Conditions not read yet

Source summary

The plugin install flow in Claude Code and Claude Desktop checked out a marketplace's pinned commit SHA using git checkout without verifying that the resulting HEAD matched the pinned SHA. An attacker controlling a plugin's upstream repository could create a branch named identically to the pinned 40-character SHA, causing the checkout to silently resolve to the attacker's branch tip instead of the reviewed commit, resulting in attacker-controlled code being installed bypassing the pinned hash. Exploitation required a user to install a malicious plugin, pin to a safe hash, and for the plugin so

Affected
@anthropic-ai/claude-code <2.1.179
Fixed in
2.1.179
ID
GHSA-pq7j-f95f-qfcv
Open the alert

Managed Settings Not Applied When a Stored API Key Was Preferred Over Enterprise Sign-In

@anthropic-ai/claude-code · 29 Sep

Low
Conditions not read yet

Source summary

Claude Code selected an API key stored by Claude Code, for example from an earlier /login or written directly to its configuration, ahead of the user's valid Claude Enterprise or Team sign-in when fetching the organization's server-managed settings, even though the session itself authenticated with the Enterprise or Team account. When the settings endpoint rejected that stored key, the session started without the organization's server-managed policy (such as permission deny rules, model restrictions and managed-only locks) or, if a previously cached copy existed on the machine, kept applying t

Affected
@anthropic-ai/claude-code >=2.0.68 <2.1.260
Fixed in
2.1.260
ID
GHSA-gfvf-j8jh-jxxw
Open the alert