CVE-2026-103435
Description
A flaw was found in claude-code. An attacker with write access to a shared workspace can achieve arbitrary file modification and privilege escalation by exploiting a time-of-check to time-of-use (TOCTOU) race condition. By replacing a project file with a symbolic link between the permission check and the write operation, an attacker can bypass workspace restrictions and overwrite sensitive files outside the project sandbox.
Statement
A flaw was found in Claude Code (claude-code), which is bundled in the Red Hat OpenShift Dev Spaces plugin registry container image (devspaces/pluginregistry-rhel9) in the 3.28, 3.29, and 3.30 streams. 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. An attacker with write access to a shared workspace could exploit this time-of-check to time-of-use (TOCTOU) race condition by atomically replacing a project file with a symbolic link between the permission check and the write operation, causing Claude Code to follow the symlink and write to an arbitrary file outside the project sandbox. Exploitation requires winning a race against the write operation, but could allow a lower-privileged attacker to redirect benign edits to sensitive files (such as shell configuration) in a higher-privileged session, resulting in arbitrary file modification and privilege escalation. Red Hat rates this flaw as moderate impact (CVSS 7.0, AV:L/AC:H/PR:L) because exploitation requires local access with write access to the shared workspace and successfully winning a race; the upstream advisory rates it High (CVSS 7.7) using a CVSS v4 vector that assumes a network attack vector and no privileges. A fix is being pursued for the affected Red Hat OpenShift Dev Spaces streams with the resolution delegated to the responsible component team.
Mitigation
Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability. Upstream advises that users on standard Claude Code auto-update have already received the fix and that users performing manual updates should update to the latest version.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 7 | N/A | N/A |
| Attack Vector | Local | N/A | N/A |
| Attack Complexity | High | N/A | N/A |
| Privileges Required | Low | N/A | N/A |
| User Interaction | None | N/A | N/A |
| Scope | Unchanged | N/A | N/A |
| Confidentiality | High | N/A | N/A |
| Integrity Impact | High | N/A | N/A |
| Availability Impact | High | N/A | N/A |
Vector
Red Hat: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
Understanding the Weakness (CWE)
Integrity,Other
Technical Impact: Alter Execution Logic; Unexpected State
The attacker can gain access to otherwise unauthorized resources.
Integrity,Other
Technical Impact: Modify Application Data; Modify Files or Directories; Modify Memory; Other
Race conditions such as this kind may be employed to gain read or write access to resources which are not normally readable or writable by the user in question.
Integrity,Other
Technical Impact: Other
The resource in question, or other resources (through the corrupted one), may be changed in undesirable ways by a malicious user.
Non-Repudiation
Technical Impact: Hide Activities
If a file or other resource is written in this method, as opposed to in a valid way, logging of the activity may not occur.
Non-Repudiation,Other
Technical Impact: Other
In some cases it may be possible to delete files a malicious user might not otherwise have access to, such as log files.
Other
Technical Impact: Unexpected State
The product may perform invalid actions when the resource is in an unexpected state.
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