Reference page — cumulative record through Wednesday, August 19, 2026 UTC. Reference pages update as the archive grows; only dated daily editions are immutable pages of record.
n/a n/a — An undocumented and unsafe feature in the PLY (Python Lex-Yacc) library 3.11 allows Remote Code Execution (RCE) via the `picklefile` para…
AV AC PR UI S C I A CVSS EPSS %ile KEV
N L N N U H H H 9.8 .1715 96.8 —
AFFECTED
Product Versions Fixed
n/a n/a – —
TIMELINE
Aug 16 Reserved by mitre
Jan 20 Published (CNA: mitre)
Aug 7 EXPLOIT PUBLISHED — CVE-2025-56005. Public exploit reference added.
Description
An undocumented and unsafe feature in the PLY (Python Lex-Yacc) library 3.11 allows Remote Code Execution (RCE) via the `picklefile` parameter in the `yacc()` function. This parameter accepts a `.pkl` file that is deserialized with `pickle.load()` without validation. Because `pickle` allows execution of embedded code via `__reduce__()`, an attacker can achieve code execution by passing a malicious pickle file. The parameter is not mentioned in official documentation or the GitHub repository, yet it is active in the PyPI version. This introduces a stealthy backdoor and persistence risk. NOTE: A third-party states that this vulnerability should be rejected because the proof of concept does not demonstrate arbitrary code execution and fails to complete successfully.
Lifecycle
Complete event history — 3 events, chronological
| Date | Event | Detail |
|---|
| August 16, 2025 | Reserved | Reserved by mitre |
| January 20, 2026 | Published | Published (CNA: mitre) |
| August 7, 2026 | EXPLOIT PUBLISHED | EXPLOIT PUBLISHED — CVE-2025-56005. Public exploit reference added. |
Affected
Affected products and packages — 1 row
| Vendor | Product / Package | Ecosystem | Version introduced | Fixed |
|---|
| n/a | n/a | — | n/a | — |
About this page
This is a reference page, not a dated page of record. It assembles the complete lifecycle of CVE-2025-56005 from the CVE Program record, NVD enrichment, the CISA KEV catalog, EPSS, and OSV advisories. The box score's numbers (CVSS, EPSS, KEV status) are current as of Wednesday, August 19, 2026 UTC and are re-derived as the archive grows; only dated daily editions are immutable pages of record. The authoritative source for this identifier is cve.org.