pip would incorrectly handle doubly-encoded package URLs from indexes

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS 4.0

5.6 · CVSS:4.0/AV:N/AC:H/AT:P/PR:H/UI:A/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N · score source

EPSS

• CVE-2026-13346: 0.29% estimated exploitation activity in the next 30 days; percentile 21.88 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

pip would incorrectly handle doubly-encoded package URLs from indexes allowing for files to be installed to arbitrary locations on disk even when installing wheels. This vulnerability requires downloading or installing a package from a malicious package index to succeed, malicious packages alone are not able to exploit this vulnerability. Note that this vulnerability only materially impacts users running pip download with the --only-binary option as installing source distributions from an untrusted index is already an unsafe operation that executes code during install time.

Published by the source

29 Jul 2026, 21:30 UTC

Last modified by the source

1 Sep 2026, 18:57 UTC

Source last checked

26 Oct 2026, 13:50 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-qwm4-qh6w-59xr

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# Patch Next advisory brief: CVE-2026-13346

Advisory: pip would incorrectly handle doubly-encoded package URLs from indexes
IDs: CVE-2026-13346, GHSA-qwm4-qh6w-59xr
Record: https://patchnext.com/advisories/cve-2026-13346 (revision 1, source checked 26 Oct 2026, 13:50 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 5.6)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: pip 26.2.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- PyPI pip: affected < 26.2.0; fixed in 26.2.0

## Suggested inspection (read-only)
- `python -m pip show pip`: prints the installed version. Run with the environment that serves production active.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on pip.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-qwm4-qh6w-59xr (GitHub-reviewed advisory GHSA-qwm4-qh6w-59xr lists affected ranges: PyPI pip >=0 <26.2.0)

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