CVE-2026-104843: Uv Path Traversal Vulnerability

MODERATE
Advisory Identifier: GHSA-2cv4-cqwr-gwf7
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CWE-22
Published
Advisory Summary

CVE-2026-104843 is a MODERATE path traversal vulnerability (CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')) affecting Uv libraries in the PyPI ecosystem. The issue involves path traversal on windows through wheel extraction. Remediation is available by upgrading affected packages to version 0.12.18.

CVE-2026-104843 at a Glance

CVE Identifier CVE-2026-104843
GHSA Identifier GHSA-2cv4-cqwr-gwf7
Severity MODERATE
CVSS v3.1 Base Score N/A
CWE Classification CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
Affected Product Uv
Package Ecosystem PyPI
Published Date
Last Updated

How to Fix CVE-2026-104843

To remediate this vulnerability, upgrade all affected Uv dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

uv fixed: 0.12.18 
pip install uv>=0.12.18
uv fixed: 0.12.18 
Upgrade uv to 0.12.18
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

pip show uv

How to Check if You Are Affected

To determine whether your Python environment is affected by CVE-2026-104843, inspect your installed packages using pip:

pip show uv

Analyze the terminal output to locate any version of Uv in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 0.12.18), your application is affected.

Note: The pip show uv command checks currently installed packages in your active Python environment.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal'), where the product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory. In Uv, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

### Impact In versions of uv from 0.12.7 to 0.12.18 on Windows, uv could be induced into writing a file outside of the installation prefix during wheel installation. A malicious wheel could use this to place an executable outside of the intended environment, including in a directory already present on the user's PATH. This vulnerability only affects Windows hosts; no other platforms are affected. ### Patches uv 0.12.18 and newer address this vulnerability. Users are encouraged to upgrade to 0.12.18. ### Workarounds There is no workaround other than upgrading to uv 0.12.18.

CVE-2026-104843 Affected Uv Versions

2 component(s)
Fixed Versions:
0.12.18
Product / Package Ecosystem Affected Versions Fixed Version
uv
pypi/uv
PyPI
≥ 0.12.7
< 0.12.18
0.12.18
uv
 crates.io
≥ 0.12.7
< 0.12.18
0.12.18

References

GitHub Advisory / Wiki ADVISORY
https://github.com/astral-sh/uv/security/advisories/GHSA-2cv4-cqwr-gwf7
NVD — CVE-2026-104843 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-104843
Uv Source Repository REPOSITORY
https://github.com/astral-sh/uv/pull/21923
Security Fix Commit FIX COMMIT
https://github.com/astral-sh/uv/commit/67169645278ce082638d619beefa6d062540843b
Uv Source Repository REPOSITORY
https://github.com/astral-sh/uv
Uv Release RELEASE
https://github.com/astral-sh/uv/releases/tag/0.12.18

Frequently Asked Questions

What is CVE-2026-104843?
CVE-2026-104843 is a security vulnerability in Uv involving Path traversal on Windows through wheel extraction under CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal').
Which Uv versions are affected?
Affected versions include releases prior to 0.12.18 across affected packages: uv.
What version fixes CVE-2026-104843?
Upgrading to 0.12.18 (or the latest patched release for your respective branch) resolves the vulnerability.
Is uv affected?
Yes, uv is affected in releases prior to 0.12.18. Upgrade your dependency to 0.12.18 or later.
What CWE is associated with CVE-2026-104843?
CVE-2026-104843 is classified under CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal') (The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory.).
How can I check PyPI dependencies for CVE-2026-104843?
Run the dependency tree command: 'pip show uv'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-2cv4-cqwr-gwf7",
  "modified" : "2026-10-05T23:42:09Z",
  "published" : "2026-10-05T23:42:09Z",
  "aliases" : [ "CVE-2026-104843" ],
  "summary" : "uv: Path traversal on Windows through wheel extraction",
  "details" : "### Impact\n\nIn versions of uv from 0.12.7 to 0.12.18 on Windows, uv could be induced into writing a file outside of the installation prefix during wheel installation.\n\nA malicious wheel could use this to place an executable outside of the intended environment, including in a directory already present on the user's PATH. \n\nThis vulnerability only affects Windows hosts; no other platforms are affected.\n\n### Patches\n\nuv 0.12.18 and newer address this vulnerability. Users are encouraged to upgrade to 0.12.18.\n\n### Workarounds\n\nThere is no workaround other than upgrading to uv 0.12.18.",
  "severity" : [ {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "PyPI",
      "name" : "uv"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0.12.7"
      }, {
        "fixed" : "0.12.18"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "crates.io",
      "name" : "uv"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0.12.7"
      }, {
        "fixed" : "0.12.18"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/astral-sh/uv/security/advisories/GHSA-2cv4-cqwr-gwf7"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-104843"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/astral-sh/uv/pull/21923"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/astral-sh/uv/commit/67169645278ce082638d619beefa6d062540843b"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/astral-sh/uv"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/astral-sh/uv/releases/tag/0.12.18"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-22" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-10-05T23:42:09Z",
    "nvd_published_at" : "2026-10-02T16:16:46Z"
  }
}