CVE-2026-53956: Rattler cache Path Traversal Vulnerability

MODERATE
Advisory Identifier: GHSA-h672-p7h7-97v9
Share
CVSS 5.4
CWE-73 CWE-22
Published
Advisory Summary

CVE-2026-53956 is a MODERATE (CVSS 5.4) path traversal vulnerability (CWE-73: External Control of File Name or Path) affecting Rattler cache libraries in the crates.io ecosystem. The issue involves rattler vulnerable to package cache path traversal via conda package build string. Remediation is available by upgrading affected packages to version 0.9.0, 0.24.0.

CVE-2026-53956 at a Glance

CVE Identifier CVE-2026-53956
GHSA Identifier GHSA-h672-p7h7-97v9
Severity MODERATE
CVSS v3.1 Base Score 5.4
CWE Classification CWE-73: External Control of File Name or Path
Affected Product Rattler cache
Package Ecosystem crates.io
Published Date
Last Updated

Security Impact

CVSS: 5.4

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:L).

Attack Vector Network (AV:N)
Attack Complexity Low (AC:L)
Privileges Required None (PR:N)
User Interaction Required (UI:R)
Scope Unchanged (S:U)
Confidentiality None (C:N)
Integrity Low (I:L)
Availability Low (A:L)

How to Fix CVE-2026-53956

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

rattler_cache fixed: 0.9.0 
Upgrade rattler_cache to 0.9.0
py_rattler fixed: 0.24.0 
pip install py_rattler>=0.24.0
Verify Direct and Transitive Dependencies

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

inspect dependencies for rattler_cache

How to Check if You Are Affected

To determine whether your application is affected by CVE-2026-53956, inspect your project dependencies for Rattler cache:

inspect dependencies for rattler_cache

Analyze the terminal output to locate any version of Rattler cache in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 0.9.0), your application is affected.

Note: Verify declared build manifests and deployed runtime container environments.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-73: External Control of File Name or Path, where the product allows user input to control or influence paths or file names that are used in filesystem operations. In Rattler cache, 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

`rattler_cache` and `py-rattler` were vulnerable to package-cache path traversal when handling package metadata from conda channels. During cache materialization, the `ratter_cache` code used the package record `build` string as part of a cache key that was joined into a filesystem path. A malicious or untrusted channel could publish repodata with path separators or traversal components in that field, causing package contents to be written outside the configured package cache directory. The issue requires use of a malicious or otherwise untrusted conda channel. Curated channels that validate package metadata are not expected to allow malformed build strings of this form. Users should upgrade to a patched version and avoid untrusted conda channels.

CVE-2026-53956 Affected Rattler cache Versions

2 component(s)
Fixed Versions:
0.9.00.24.0
Product / Package Ecosystem Affected Versions Fixed Version
rattler_cache
 crates.io
< 0.9.0
0.9.0
py_rattler
pypi/py_rattler
PyPI
< 0.24.0
0.24.0

References

GitHub Advisory / Wiki ADVISORY
https://github.com/conda/rattler/security/advisories/GHSA-h672-p7h7-97v9
Rattler cache Source Repository REPOSITORY
https://github.com/conda/rattler

Frequently Asked Questions

What is CVE-2026-53956?
CVE-2026-53956 is a security vulnerability in Rattler cache involving Rattler vulnerable to package cache path traversal via conda package build string under CWE-73: External Control of File Name or Path.
Which Rattler cache versions are affected?
Affected versions include releases prior to 0.9.0, 0.24.0 across affected packages: rattler_cache, py_rattler.
What version fixes CVE-2026-53956?
Upgrading to 0.9.0, 0.24.0 (or the latest patched release for your respective branch) resolves the vulnerability.
Is rattler_cache affected?
Yes, rattler_cache is affected in releases prior to 0.9.0. Upgrade your dependency to 0.9.0 or later.
Is py_rattler affected?
Yes, py_rattler is affected in releases prior to 0.24.0. Upgrade your dependency to 0.24.0 or later.
What is the CVSS score of CVE-2026-53956?
CVE-2026-53956 has a CVSS v3.1 base score of 5.4 (MODERATE) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:L.
What CWE is associated with CVE-2026-53956?
CVE-2026-53956 is classified under CWE-73: External Control of File Name or Path (The product allows user input to control or influence paths or file names that are used in filesystem operations.).
How can I check crates.io dependencies for CVE-2026-53956?
Run the dependency tree command: 'inspect dependencies for rattler_cache'. 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-h672-p7h7-97v9",
  "modified" : "2026-07-09T23:20:12Z",
  "published" : "2026-07-09T23:20:12Z",
  "aliases" : [ "CVE-2026-53956" ],
  "summary" : "Rattler vulnerable to package cache path traversal via conda package build string",
  "details" : "`rattler_cache` and `py-rattler` were vulnerable to package-cache path traversal when handling package metadata from conda channels.\n\nDuring cache materialization, the `ratter_cache` code used the package record `build` string as part of a cache key that was joined into a filesystem path. A malicious or untrusted channel could publish repodata with path separators or traversal components in that field, causing package contents to be written outside the configured package cache directory.\n\nThe issue requires use of a malicious or otherwise untrusted conda channel. Curated channels that validate package metadata are not expected to allow malformed build strings of this form.\n\nUsers should upgrade to a patched version and avoid untrusted conda channels.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:L"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "crates.io",
      "name" : "rattler_cache"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "0.9.0"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 0.8.2"
    }
  }, {
    "package" : {
      "ecosystem" : "PyPI",
      "name" : "py_rattler"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "0.24.0"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 0.23.2"
    }
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/conda/rattler/security/advisories/GHSA-h672-p7h7-97v9"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/conda/rattler"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-22", "CWE-73" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-07-09T23:20:12Z",
    "nvd_published_at" : null
  }
}