# CVE-2026-31072: APScheduler's JSONSerializer and CBORSerializer are vulnerable to Remote Code Execution (RCE) via Insecure Deserialization

> Attackers can achieve remote code execution in applications using APScheduler by submitting crafted JSON or CBOR payloads to vulnerable serializers.

- **Severity:** Critical 9.8 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/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:** Not needed
- **Fix available:** No
- **Published:** 19 May 2026
- **Updated:** 15 Jul 2026
- **Also known as:** GHSA-9cfw-f3f9-7mm7, PYSEC-2026-282

## What is CVE-2026-31072?

CVE-2026-31072 is a critical unsafe deserialization vulnerability in n/a, published on 19 May 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

The JSONSerializer and CBORSerializer in APScheduler (all versions including 3.10.x and 4.0.0a5) are vulnerable to Remote Code Execution (RCE) via Insecure Deserialization. The unmarshal_object function allows for arbitrary class instantiation and state injection by dynamically importing modules and calling __setstate__ on any class available in the Python environment. An attacker can exploit this by submitting a specially crafted JSON or CBOR payload to an application using these serializers

Weakness: CWE-502 (Deserialization of Untrusted Data)

## Which versions are affected by CVE-2026-31072?

3 open source packages ship an affected version, including apscheduler.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `apscheduler` | PyPI | From 4.0.0a1 to 4.0.0a6 | None |
| `apscheduler` | PyPI | From 4.0.0a1 to 4.0.0a6 | None |
| `apscheduler` | PyPI | From 4.0.0a1 to 4.0.0a6 | None |

## How do I fix CVE-2026-31072?

No fix has been published for CVE-2026-31072 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-31072 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-31072 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-31072 and fix it if it is affected.

What it is: CVE-2026-31072 is a critical unsafe deserialization vulnerability in n/a, published on 19 May 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-31072 exists.

Affected packages and fixed versions:
- apscheduler (PyPI): affected from 4.0.0a1 up to 4.0.0a6; no fix listed
- apscheduler (PyPI): affected from 4.0.0a1 up to 4.0.0a6; no fix listed
- apscheduler (PyPI): affected from 4.0.0a1 up to 4.0.0a6; no fix listed

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-2026-31072/ (Markdown: https://insights.sbomify.com/CVE-2026-31072/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-31072
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-31072
- OSV: https://osv.dev/vulnerability/CVE-2026-31072

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-31072/
Summaries are generated and may contain mistakes; the official description above is the record.