CVE-2026-3087· NVD / CVE Program· CNA PSF

shutil.unpack_archive() doesn't check for Windows absolute paths in ZIPs

Noroxi assessment

Priority: Monitor (action score 24/100)

The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
Probability of exploitation in the next 30 days: 0.73% (FIRST EPSS); higher than 53.8% of all records.
Anyone who can reach it over the internet can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
Fixed version: Python Software Foundation CPython 3.10.21, 3.11.16, 3.12.14; azl3 python3 3.12.9-13 on Azure Linux 3.0 3.12.9-14; azl3 python3 3.12.9-14 on Azure Linux 3.0 3.12.9-14.

Low priority for now. Upgrade to Python Software Foundation CPython 3.10.21, 3.11.16, 3.12.14; azl3 python3 3.12.9-13 on Azure Linux 3.0 3.12.9-14; azl3 python3 3.12.9-14 on Azure Linux 3.0 3.12.9-14 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

If `shutil.unpack_archive()` is given a ZIP archive with an absolute Windows path containing a drive (`C:\\...`) then the archive will be extracted outside the target directory which is different than other operating systems. Only Windows is affected by this vulnerability.

MediumCVSS 6.0 · v4.0—No exploit Fix available

Path traversal

Published: Apr 27, 2026
Updated: Aug 13, 2026
EPSS: 0.7% · 53th percentile
CWE: CWE-22

Report tools

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Action score

Monitor

Low priority for now.

CVSS: 24 / 40 · 6.0 / 10
CISA KEV: 0 / 30 · Not listed
EPSS: 0 / 30 · 0.7%

CISA SSVC decision

Exploitation: none
Automatable: no
Technical impact: partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD: —
CNA · PSF: 6.0; NVD has not scored this yet; the score shown is the CNA’s.

CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

Not in KEV: no record of exploitation in the wild
No public exploit code on record
A fix has been released

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

Vendor	Product	CPE
python	python	cpe:2.3:a:python:python
microsoft	windows	cpe:2.3:o:microsoft:windows

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

python pythonup to 3.14.4 inclusive
python python3.15.0

Versions reported by the vendor

Affected version ranges reported by the assigning authority (PSF). Independent of NVD's CPE analysis and usually ahead of it.

Python Software Foundation CPython
- before 3.10.21affected · python
- 3.11.0 and later · before 3.11.16affected · python
- 3.12.0 and later · before 3.12.14affected · python
- 3.13.0 and later · before 3.13.14affected · python
- 3.14.0a1 and later · before 3.14.5rc1affected · python
- 3.15.0a1 and later · before 3.15.0b1affected · python

Same product

python: all records

Other highest-scoring records for the same primary product.

CVE-2016-5636Integer overflow in the get_data function in zipimport.c in CPython (aka Python) before 2.7.12, 3.x before 3.4.5, and 3.5.x before 3.5.2 all
47Plan
CVE-2007-4559Directory traversal vulnerability in the (1) extract and (2) extractall functions in the tarfile module in Python allows user-assisted remot
47Plan
CVE-2021-3177Python 3.x through 3.9.1 has a buffer overflow in PyCArg_repr in _ctypes/callproc.c, which may lead to remote code execution in certain Pyth
46Plan

Published before and after this one in the same product

← EarlierCVE-2026-4519Mar 20, 2026 · webbrowser.open() allows leading dashes in URLs
28Monitor
← EarlierCVE-2026-6019Apr 22, 2026 · BaseCookie.js_output() does not neutralize embedded characters
8Monitor
Later →CVE-2026-7210May 11, 2026 · The expat and elementtree parsers use insufficient entropy for XML hash-flooding protection
25Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / package	Fixed version	Source
Python Software Foundation CPython	3.10.21	Vendor (CNA)
Python Software Foundation CPython	3.11.16	Vendor (CNA)
Python Software Foundation CPython	3.12.14	Vendor (CNA)
Python Software Foundation CPython	3.13.14	Vendor (CNA)
Python Software Foundation CPython	3.14.5rc1	Vendor (CNA)
Python Software Foundation CPython	3.15.0b1	Vendor (CNA)
azl3 python3 3.12.9-13 on Azure Linux 3.0	3.12.9-14 · CBL-Mariner Releases	Microsoft (MSRC)
azl3 python3 3.12.9-14 on Azure Linux 3.0	3.12.9-14 · CBL-Mariner Releases	Microsoft (MSRC)
cbl2 python3 3.9.19-19 on CBL-Mariner 2.0	Release Notes	Microsoft (MSRC)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

Seth Larson (https://github.com/sethmlarson)coordinator
GGAutomaton (https://github.com/GGAutomaton)reporter
Serhiy Storchaka (https://github.com/serhiy-storchaka)remediation developer

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

Anyone who can reach it over the internet can trigger it.
A low-privileged account is enough.
No user action is required.
No special conditions are required; it is repeatable.

If successful

Confidentiality
Integrity
Availability

Attack vector: Network
Attack complexity: Low
Privileges required: Low
User interaction: None
Scope: X

Weakness class (CWE)

CWE-22 · Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')

CVSS vector

CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

nvd-secondary

Root cause

A user-supplied file name is joined with the allowed directory, but the result is never checked to confirm it is still inside that directory.

The bug in code

The whole CWE-22 class

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

Vulnerable

1const file = path.join(ROOT, req.query.name);
2res.sendFile(file);

Fixed

1const file = path.resolve(ROOT, req.query.name);
2if (!file.startsWith(ROOT + path.sep)) {
3  return res.sendStatus(400);
4}
5res.sendFile(file);

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

Attack patterns (CAPEC)

ATT&CK techniques

—

Change log

Fix✗ → ✓Sep 28, 2026, 10:10 PM UTC

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References

github.com/python/cpython/commit/1071290169f85c09cf767c1099564a9426cdc7e8

Show all references (12 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records