Prevent shadowing stdlib in gzip/tarfile/zipfile CLI during extraction
- Exploited
- No known exploitation
- Fix
- Fixed in 3.16.0
- Who is exposed
- Not reported
Do first: Upgrade to a fixed version: 3.16.0.
- Last modified
- Whether it needs action now or is a reference record, by fixed rules, with why. Last checked is when cve.now last re-read it.What do these mean? →
- Reference
- Last checked
- A 0-100 score for how much a CVE matters across the industry: exploitation, exposure, how widely the software is used, severity and whether a fix exists.What do these mean? →
- 6/100 · provisional
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
- Exploitation: none
- Automatable: no
- Technical impact: total
Summary
The Python standard library's gzip, tarfile, and zipfile command-line tools can be tricked into running attacker-supplied code. An attacker who can get a crafted archive extracted in the current directory, with a user taking action to run it, can have a malicious script such as traceback.py run locally with the user's privileges, which requires local access and low-privilege login.
Written by anthropic/claude-haiku-5.5 from the sources below. Verify against them.
Read the original description
When tarfile or zipfile command line interface (CLI) is used to
decompress an archive, a Python script shadowing the stdlib can be
created. Then if an error occurs during decompressing the next file,
the newly created Python script is executed. This is especially true
if the created Python is called traceback.py. The problem is that
Python adds the current directory to sys.path when python -m MODULE is
run, and the archive is also decompressed in the current directory.
The fix removes sys.path[0] in gzip, tarfile and zipfile command line
interface to prevent shadowing standard library modules from extracted
files.
cve.now Index
- Exploitation0/40No signal
- Exposure?/25Unknown. No advisory context yet
- Reach?/20Unknown. No tracked technology or package matched
- Severity6.3/10CVSS 5.3, total technical impact per CISA
- No patch0/5No signal
What would change the score
- Would score about 61 if added to CISA KEV
- Would score about 56 if CISA's SSVC rates exploitation active
- Would score about 28 if advisories confirm default setups are exposed
What to do
Upgrade to a fixed version: 3.16.0.
Check your systems with an agent
Paste this into a coding or ops agent. It checks your systems read-only and reports a table per asset.
Check whether my systems are affected by CVE-2026-115791 (Prevent shadowing stdlib in gzip/tarfile/zipfile CLI during extraction), using the cve.now data below. Rules: work read-only. Do not run exploit code, proof-of-concept scripts or scanners that send attack payloads, and do not change any configuration, package, image or deployment. Report findings only. What cve.now has for CVE-2026-115791 (entry last updated 2026-11-10): Affected: - Python Software Foundation CPython: fixed in 3.16.0 Fixed versions: 3.16.0. Setup: unknown whether the bug needs a non-default feature or setting. Check the advisory. CISA KEV: CVE-2026-115791 is not listed as of cve.now's last read. This KEV status is for CVE-2026-115791 only. If you also check another CVE, look up its own KEV status; never assume it from this one. How to check: - Installed software: check what is actually running, not what a repo declares. Read the version from each host, container image and Kubernetes node (the binary's version output, the OS package database, image layers), and check whether the conditions above hold there. Distribution packages may carry a backported fix under an older version number; confirm against the distribution's own advisory. Verify against the linked advisories before concluding, and cite the date you read each one: - https://mail.python.org/archives/list/security-announce@python.org/thread/ZKKA4Q7B35JEHSDIJNZ6TYKRDQJUHDAG/ - https://github.com/python/cpython/pull/161706 - https://github.com/python/cpython/issues/161705 Do not conclude an asset is unaffected unless you checked it and the evidence covers both its version and the conditions above. If you could not check something, mark it unknown and say what is missing. Report a table with one row per asset and these columns: Asset | Version or build | Status (affected, fixed, not applicable, unknown) | Compensating controls | Exposure (internet-facing, internal, none) | Evidence | Next action. Entry: https://cve.now/CVE-2026-115791 For follow-up questions, use the cve.now MCP server at https://mcp.cve.now/mcp (no authentication), for example get_vulnerability with id CVE-2026-115791.
Timeline
- CVE published
- First seen by cve.now
- CISA SSVC assessment
Exploitation: none · Automatable: no · Technical impact: total
- Record last updated
Affected versions
- Python Software Foundation CPython
fixed in 3.16.0
Evidence 5
Vendor advisory · 1
Establishes: Affected and fixed versions.
- Advisory
CVE record · 2
Establishes: The identifier and description.
- Record
- Record
Other links · 2
- Patch
- Report
Corrections
None so far.
Something wrong on this page? Report an error. Every fix is listed here.
Questions about CVE-2026-115791
Is CVE-2026-115791 being exploited?
It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.Source: cve.now feed data
Which versions are affected by CVE-2026-115791?
CPython: before 3.16.0.Source: cve.now feed data
How do I fix CVE-2026-115791?
Upgrade to a fixed version: 3.16.0.Source: cve.now feed data