PatchSiren

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
2026-06-02
Advisory published
2026-05-27
Advisory updated
2026-06-02

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.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-45136 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-45136

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-45136 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-45136

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.