high CVSS 7.8 EPSS <0.1%

CVE-2026-45136·Python vulnerability

claude-code-cache-fix is a cache optimization proxy for Claude Code. From 3.5.0 to before 3.5.2, tools/quota-statusline.sh (introduced in v3.5.0) interpolates Claude Code's hook stdin payload directly into a Python triple-quoted string literal. A ''' byte sequence in any user-controlled field of the payload closes the literal early and lets following bytes execute as Python in the user's Claude Code process. This vulnerability is fixed in 3.5.2.

Severity
high
Software
Python
Fixed in
3.5.2
Published

How likely is exploitation

FIRST's Exploit Prediction Scoring System puts the probability of this CVE being exploited in the next 30 days at <0.1% — higher than 6% of all published CVEs. EPSS is an independent forecast of exploitation, not a severity rating: it says nothing about how much damage a successful attack does, which is what a CVSS score measures.

Read the two together. CVE-2026-45136 scores 7.8 on CVSS, so a successful attack would be serious — but at <0.1%, almost nobody is currently attempting it. That is a different situation from a flaw under mass exploitation, and it is usually the difference between patching on your next maintenance window and patching tonight.

Affected versions

From: 3.5.0

Until: 3.5.2

Fixed in: 3.5.2

How to fix this CVE

Update the claude-code-cache-fix component to version 3.5.2 or later to remediate this critical string interpolation vulnerability. The affected versions (3.5.0–3.5.1) allow arbitrary Python code execution through malformed payload injection in the quota-statusline.sh script. Immediately patch your Python environment and verify the update completion before resuming Claude Code operations.

sudo dnf check-update && sudo dnf upgrade python3 && pip install --upgrade claude-code-cache-fix>=3.5.2

Defensia detects this vulnerability

How to check if you are affected

  1. Check installed version: pip show claude-code-cache-fix | grep Version
  2. Verify if quota-statusline.sh exists and is active: ls -la ~/.claude/tools/quota-statusline.sh (or appropriate installation path)
  3. Search logs for triple-quote sequences in Claude Code hook payloads: grep -r "'''" ~/.claude/logs/ or journalctl -u claude-code | grep "'''"
  4. Confirm patch applied: pip show claude-code-cache-fix | grep Version should report 3.5.2 or later

FAQ

What is CVE-2026-45136?

This vulnerability exists in the quota-statusline.sh script bundled with claude-code-cache-fix versions 3.5.0–3.5.1, where user-controlled hook payload data is directly interpolated into a Python string literal without escaping, allowing attackers to inject and execute arbitrary Python code by crafting payloads containing triple-quote sequences.

Is CVE-2026-45136 being actively exploited?

No, this vulnerability is not listed in CISA's Known Exploited Vulnerabilities (KEV) catalog, and no public exploits are currently available, though the attack surface depends on whether users expose Claude Code hooks to untrusted input sources.

What versions of Python are affected by CVE-2026-45136?

claude-code-cache-fix versions 3.5.0 through 3.5.1 are vulnerable; the fix is available in version 3.5.2 and later.

How do I check if my server is vulnerable to CVE-2026-45136?

Run: pip show claude-code-cache-fix | grep Version. If the version is 3.5.0 or 3.5.1, your installation is vulnerable and requires immediate patching.

Does Defensia detect CVE-2026-45136?

Yes — Defensia's CVE advisory scanner compares installed package versions against the NVD database. If claude-code-cache-fix is installed on a monitored server, CVE-2026-45136 will appear in your dashboard with remediation steps.

Related Python CVEs

CVE-2026-25632CVSS 10EPyT-Flow is a Python package designed for the easy generation of hydraulic and water quality scenario data of water distribution networks. Prior to 0.16.1, EPyT-Flow’s REST API parses attacker-controlled JSON request bodies using a custom deserializer (my_load_from_json) that supports a type field. When type is present, the deserializer dynamically imports an attacker-specified module/class and instantiates it with attacker-supplied arguments. This allows invoking dangerous classes such as subprocess.Popen, which can lead to OS command execution during JSON parsing. This also affects the loading of JSON files. This vulnerability is fixed in 0.16.1.
CVE-2026-34938CVSS 10PraisonAI is a multi-agent teams system. Prior to version 1.5.90, execute_code() in praisonai-agents runs attacker-controlled Python inside a three-layer sandbox that can be fully bypassed by passing a str subclass with an overridden startswith() method to the _safe_getattr wrapper, achieving arbitrary OS command execution on the host. This issue has been patched in version 1.5.90.
CVE-2026-33054CVSS 10Mesop is a Python-based UI framework that allows users to build web applications. Versions 1.2.2 and below contain a Path Traversal vulnerability that allows any user supplying an untrusted state_token through the UI stream payload to arbitrarily target files on the disk under the standard file-based runtime backend. This can result in application denial of service (via crash loops when reading non-msgpack target files as configurations), or arbitrary file manipulation. This vulnerability heavily exposes systems hosted utilizing FileStateSessionBackend. Unauthorized malicious actors could interact with arbitrary payloads overwriting or explicitly removing underlying service resources natively outside the application bounds. This issue has been fixed in version 1.2.3.
CVE-2026-28505CVSS 10Tautulli is a Python based monitoring and tracking tool for Plex Media Server. Prior to version 2.17.0, the str_eval() function in notification_handler.py implements a sandboxed eval() for notification text templates. The sandbox attempts to restrict callable names by inspecting code.co_names of the compiled code object. However, co_names only contains names from the outer code object. When a lambda expression is used, it creates a nested code object whose attribute accesses are stored in code.co_consts, NOT in code.co_names. The sandbox never inspects nested code objects. This issue has been patched in version 2.17.0.
CVE-2026-26030CVSS 9.9Semantic Kernel, Microsoft's semantic kernel Python SDK, has a remote code execution vulnerability in versions prior to 1.39.4, specifically within the `InMemoryVectorStore` filter functionality. The problem has been fixed in version `python-1.39.4`. Users should upgrade this version or higher. As a workaround, avoid using `InMemoryVectorStore` for production scenarios.

References

Track CVEs across your fleet automatically

Defensia scans your Linux servers and tells you exactly which ones are running vulnerable versions — including CVE-2026-45136. Free for 1 server.

Get started free