# CVE-2026-14535: Fickling MLAllowlist analysis pass rendered inoperative by shared mutable state in AnalysisContext.shorten_code()

> Shared mutable state disables the ML allowlist check, allowing arbitrary code execution via pickle deserialization of standard library modules.

- **Severity:** High 8.8 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 4 Jul 2026
- **Updated:** 6 Jul 2026
- **Also known as:** GHSA-cffv-grgg-g429, GHSA-mgx3-9w7v-8674, PYSEC-2026-2150

## What is CVE-2026-14535?

CVE-2026-14535 is a high-severity unsafe deserialization vulnerability in trailofbits fickling, published on 4 Jul 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

### Official description

In Trail of Bits fickling versions up to and including 0.1.11, the UnsafeImportsML analysis pass unconditionally calls AnalysisContext.shorten_code(node) on every import node it inspects, regardless of whether the import is flagged as unsafe. This call registers the shortened code representation in the shared AnalysisContext.reported_shortened_code set. When the MLAllowlist analysis pass subsequently runs, it calls the same shorten_code() method, receives already_reported=True for every import, and executes a continue statement that skips its allowlist check entirely. This renders MLAllowlist dead code for all imports — it never evaluates whether an import is in the ML allowlist or not. The MLAllowlist pass was designed to catch imports of modules outside the known-safe ML ecosystem (torch, numpy, transformers, etc.) that slip past the UnsafeImports denylist. With MLAllowlist inoperative, any standard library module not in the UNSAFE_IMPORTS denylist can be invoked via pickle deserialization while fickling's check_safety() returns LIKELY_SAFE. The fickling.load() API chains check_safety() into pickle.loads() as an explicit security gate, meaning a LIKELY_SAFE verdict causes the payload to be deserialized and executed. The root cause is shared mutable state between independently-correct analysis passes — UnsafeImportsML works as designed in isolation, MLAllowlist works as designed in isolation, but the shared reported_shortened_code set causes UnsafeImportsML to poison MLAllowlist's deduplication logic.

Weakness: CWE-693 (Protection Mechanism Failure)

## Which versions are affected by CVE-2026-14535?

1 open source package ship an affected version, including fickling. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `fickling` | PyPI | All versions | 0.1.12 |

Products: Trailofbits Fickling.

## How do I fix CVE-2026-14535?

Upgrade fickling to 0.1.12 or later.

## Is CVE-2026-14535 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-14535 exists.

## Other vulnerabilities in trailofbits fickling

- [CVE-2026-22606](https://insights.sbomify.com/CVE-2026-22606/): Fickling has a bypass via runpy.run_path() and runpy.run_module() (high 8.9)
- [CVE-2026-22607](https://insights.sbomify.com/CVE-2026-22607/): Fickling Blocklist Bypass: cProfile.run() (high 8.9)
- [CVE-2026-22608](https://insights.sbomify.com/CVE-2026-22608/): Fickling vulnerable to use of ctypes and pydoc gadget chain to bypass detection (high 8.9)
- [CVE-2026-22609](https://insights.sbomify.com/CVE-2026-22609/): Fickling has Static Analysis Bypass via Incomplete Dangerous Module Blocklist (high 8.9)
- [CVE-2026-22612](https://insights.sbomify.com/CVE-2026-22612/): Fickling vulnerable to detection bypass due to "builtins" blindness (high 8.9)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-14535 and fix it if it is affected.

What it is: CVE-2026-14535 is a high-severity unsafe deserialization vulnerability in trailofbits fickling, published on 4 Jul 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-14535 exists.

Affected packages and fixed versions:
- fickling (PyPI): affected all versions; fixed in 0.1.12

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-14535/ (Markdown: https://insights.sbomify.com/CVE-2026-14535/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-14535
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-14535
- OSV: https://osv.dev/vulnerability/CVE-2026-14535

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-14535/
Summaries are generated and may contain mistakes; the official description above is the record.