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Public proof of concept

CVE-2026-31072

A public proof of concept exists; no exploitation attested.

  • Published2026-05-19
  • WeaknessCWE-502

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

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

Timeline

dates in UTC
  1. 2026-05-1916:16CVE publishedNVD

Observed activity

isMalicious corpus · updated 2026-10-23 21:37 UTC
Indicators tagged with this CVE, per day0 indicators over 7 days
Block these indicators
  • Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2026-31072?format=txt
  • CSV export: https://api.ismalicious.com/edl/cve/CVE-2026-31072?format=csv
  • TAXII collection of exploited CVEs
  • The EDL and CSV take an API key on the Pro plan.

Versions per branch

OSV
apscheduler
BranchAffectedFixed in
4.0≥ 4.0.0a1, ≤ 4.0.0a6no fix published

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Fix

No fix published by the sources we read yet. NVD record

Detection

Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof-of-concept repositories
none listed
PoC-in-GitHub

Sources

  • NVDCVE recordread 2026-10-23
  • CISA-ADPSSVC decisionpoc2026-05-20
  • OpenCVESSVC decisionpoc—
  • CISA-ADPCVSS 3.19.82026-05-20
  • CNACVSS 3.18.8read 2026-10-23
  • CISA-ADPweakness (CWE)CWE-5022026-05-20
  • CNAweakness (CWE)CWE-502read 2026-10-23
  • FIRST EPSSEPSS score1.0 %2026-10-23
  • OSVaffected packages—

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Published
2026-05-19
Last Modified
2026-07-24
NVD status
Deferred

Frequently asked questions

What is CVE-2026-31072?

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

Is CVE-2026-31072 actively exploited?

A proof-of-concept exploit exists for CVE-2026-31072, but active exploitation has not been confirmed at this time.

What is the CVSS score for CVE-2026-31072?

CVE-2026-31072 has a CVSS v3 base score of 8.8 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.

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