CVE-2025-56005Public exploit

Code execution via untrusted pickle deserialization

Published Jan 20, 2026 · Updated Jan 20, 2026

Unsafe deserialization in PLY (Python Lex-Yacc) 3.11 allows context-dependent attackers to execute code through a crafted pickle file. LRTable.read_pickle() in ply/yacc.py passes the file selected by yacc(picklefile=...) directly to pickle.load(), enabling reconstruction hooks to run during parser initialization. Exploitation requires control of the supplied file or its path; the CVE remains disputed because a published reproduction reports that the original proof of concept exits without creating its marker file.

CVSS severity9.8
Critical
EPSS probability17.51%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Unsafe deserialization in PLY (Python Lex-Yacc) 3.11 allows context-dependent attackers to execute code through a crafted pickle file. LRTable.read_pickle() in ply/yacc.py passes the file selected by yacc(picklefile=...) directly to pickle.load(), enabling reconstruction hooks to run during parser initialization. Exploitation requires control of the supplied file or its path; the CVE remains disputed because a published reproduction reports that the original proof of concept exits without creating its marker file.

The record

CVE
CVE-2025-56005
Published
Jan 20, 2026
Updated
Jan 20, 2026
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-502
Attack vector
Unavailable
Privileges
Unavailable

Timeline

How it unfolded

  1. Jan 20, 2026CVE publishedPublication date reported by the CVE source.
  2. Jan 20, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectorUnavailable in this record.
Required privilegesUnavailable in this record.

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

7.8redhat-SADPCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
9.8CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
VectorUnavailable
PrivilegesUnavailable
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-502Deserialization of Untrusted Data

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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