CVE-2025-56005
An undocumented and unsafe feature in the PLY (Python Lex-Yacc) library 3.11 allows Remote Code Execution (RCE) via the `picklefile`…
- 9.8CriticalCVSS base score
- 18.8%Exploitation in 30 daysEPSS · top 2.7% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- YesPublic exploitsa reference or SSVC says so
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.
Public exploit
An exploit or proof of concept is public: anyone can try it against an unpatched system. CISA's SSVC rates its exploitation: a proof of concept is public.
Timeline
ID reserved
By mitre
- 5 months later
· 5 months later
Published
- 8 months later
· 8 months later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| CISA-ADPADP (enrichment) | 3.1 | Critical9.8 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
| redhat-SADPADP (enrichment) | 3.1 | High7.8 | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H |
| NVDNVD · Modified | 3.1 | Critical9.8 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
- EPSS (exploitation in 30 days)
- 18.8% · top 2.7% of all CVEs (11 Nov 2026)
- CISA SSVC
- Exploitation: poc · Automatable: yes · Technical impact: total
The list uses the assigner's score when there is one, then CISA's, then NVD's: Critical 9.8.
Affected products
n/a
- affected n/a
References
References13
- https://github.com/bohmiiidd/Undocumented-RCE-in-PLY (opens in a new tab)
- https://github.com/tom025/ply_exploit_rejection (opens in a new tab)
- https://github.com/bohmiiidd/Undocumument_RCE_PLY-yacc-CVE-2025-56005 (opens in a new tab)
- https://github.com/tom025/ply_exploit_rejection/issues/1 (opens in a new tab)
- http://www.openwall.com/lists/oss-security/2026/01/23/4 (opens in a new tab)
- http://www.openwall.com/lists/oss-security/2026/01/23/5 (opens in a new tab)
- http://www.openwall.com/lists/oss-security/2026/01/28/5 (opens in a new tab)
- http://www.openwall.com/lists/oss-security/2026/01/29/1 (opens in a new tab)
- http://www.openwall.com/lists/oss-security/2026/01/29/2 (opens in a new tab)
- http://www.openwall.com/lists/oss-security/2026/01/30/1 (opens in a new tab)
- https://access.redhat.com/security/cve/CVE-2025-56005 (opens in a new tab)vdb-entryx_refsource_REDHAT
- RHBZ#2431308 (opens in a new tab)issue-trackingx_refsource_REDHAT
- https://security.access.redhat.com/data/csaf/v2/vex/2025/cve-2025-56005.json (opens in a new tab)x_sadp-csaf-vex
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2026-3342 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2025-56005)Record last updated .