PatchSiren cyber security CVE debrief
CVE-2026-45136 cnighswonger CVE debrief
A code injection vulnerability exists in claude-code-cache-fix versions 3.5.0 through 3.5.1. The tools/quota-statusline.sh script, introduced in version 3.5.0, interpolates Claude Code's hook stdin payload directly into a Python triple-quoted string literal without proper sanitization. A ''' byte sequence in any user-controlled field of the payload can prematurely close the string literal, allowing subsequent bytes to execute as arbitrary Python code within the user's Claude Code process. This vulnerability is classified as CWE-94 (Improper Control of Generation of Code) and CWE-78 (Improper Neutralization of Special Elements used in an OS Command). The issue was fixed in version 3.5.2.
- Vendor
- cnighswonger
- Product
- claude-code-cache-fix
- CVSS
- HIGH 8.6
- CISA KEV
- Not listed in stored evidence
- Original CVE published
- 2026-05-27
- Original CVE updated
- 2026-05-27
- Advisory published
- 2026-05-27
- Advisory updated
- 2026-05-27
Who should care
Organizations and individual developers using claude-code-cache-fix versions 3.5.0 or 3.5.1 as a cache optimization proxy for Claude Code. Security teams responsible for supply chain security of AI coding assistants and their supporting infrastructure. Developers maintaining forked or customized versions of the tool.
Technical summary
The vulnerability stems from improper input validation when constructing Python code dynamically. The tools/quota-statusline.sh script takes untrusted input from Claude Code's hook stdin and embeds it directly into a triple-quoted Python string literal. The triple-quote delimiter (''') serves as both the injection point and execution trigger—when present in user input, it terminates the intended string context and shifts the parser into executable Python code context. This is a classic injection pattern where metacharacters intended for data delimitation are not escaped or parameterized, allowing context boundary violation.
Defensive priority
HIGH
Recommended defensive actions
- Upgrade claude-code-cache-fix to version 3.5.2 or later
- Review any custom hook configurations for suspicious ''' sequences in payload data
- Audit Claude Code process logs for unexpected Python execution patterns
- Validate input sanitization in any locally modified versions of tools/quota-statusline.sh
Evidence notes
Vulnerability affects versions 3.5.0 to before 3.5.2. Attack vector requires local access with no privileges required and no user interaction. CVSS 4.0 vector indicates high impact to confidentiality and integrity, low impact to availability.
Official resources
2026-05-27