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CVE-2026-53956

Rattler vulnerable to package cache path traversal via conda package build string

5.4 MediumFix available

Rattler is a library that provides common functionality used within the conda ecosystem. rattler_cache prior to version 0.9.0 and py-rattler prior to version 0.24.0 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 rattler_cache version 0.9.0 or py-rattler version 0.24.0 and avoid untrusted conda channels.

Attack profile

How easy it is to exploit

Attack vector
Network
Complexity
Low
Privileges needed
None
User interaction
Required

What an attacker can affect

Confidentiality
None
Integrity
Low
Availability
Low

Exploit likelihood

0.33%Up 0.3 points since Jun 12, 2026
90%50%10%1%

What each source reports

CVE List Score used 5.4

Rattler vulnerable to package cache path traversal via conda package build string

Rattler is a library that provides common functionality used within the conda ecosystem. rattler_cache prior to version 0.9.0 and py-rattler prior to version 0.24.0 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 rattler_cache version 0.9.0 or py-rattler version 0.24.0 and avoid untrusted conda channels.

Record
CVE-2026-53956
CVSS 3.1
5.4 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:L
Weakness
CWE-22, CWE-73
Updated
2026-11-02
EUVDEUVD-2026-75141 5.4

Rattler is a library that provides common functionality used within the conda ecosystem. rattler_cache prior to version 0.9.0 and py-rattler prior to version 0.24.0 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 rattler_cache version 0.9.0 or py-rattler version 0.24.0 and avoid untrusted conda channels.

Record
EUVD-2026-75141
CVSS 3.1
5.4 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:L
Updated
2026-11-02
GitHub AdvisoriesGHSA-h672-p7h7-97v9 5.4

Rattler vulnerable to package cache path traversal via conda package build string

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.

Record
GHSA-h672-p7h7-97v9
CVSS 3.1
5.4 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:L
Weakness
CWE-22, CWE-73
Updated
2026-11-02
NVD 5.4

Rattler is a library that provides common functionality used within the conda ecosystem. rattler_cache prior to version 0.9.0 and py-rattler prior to version 0.24.0 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 rattler_cache version 0.9.0 or py-rattler version 0.24.0 and avoid untrusted conda channels.

Record
CVE-2026-53956
CVSS 3.1
5.4 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:L
Weakness
CWE-22, CWE-73
Updated
2026-11-02
OSV 5.4

Rattler vulnerable to package cache path traversal via conda package build string

Rattler is a library that provides common functionality used within the conda ecosystem. rattler_cache prior to version 0.9.0 and py-rattler prior to version 0.24.0 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 rattler_cache version 0.9.0 or py-rattler version 0.24.0 and avoid untrusted conda channels.

Record
CVE-2026-53956
CVSS 3.1
5.4 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:L
Weakness
CWE-22, CWE-73
Updated
2026-11-02
OSVGHSA-h672-p7h7-97v9 5.4

Rattler vulnerable to package cache path traversal via conda package build string

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.

Record
GHSA-h672-p7h7-97v9
CVSS 3.1
5.4 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:L
Weakness
CWE-22, CWE-73
Updated
2026-11-02
OSVPYSEC-2026-2970 5.4

Rattler vulnerable to package cache path traversal via conda package build string

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.

Record
PYSEC-2026-2970
CVSS 3.1
5.4 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:L
Updated
2026-11-02

Affected products

Affected packages

Affected packages
PackageAffectedFixed
rattler_cache
crates.io
through 0.8.2
0.9.0
py-rattler
PyPI
through 0.23.2
0.24.0
rattler_cache
crates.io
before 0.9.0
0.9.0
py-rattler
PyPI
before 0.24.0, plus listed versions
0.1.00.1.10.1.20.10.00.11.0
Show 31 moreShow less
0.12.00.13.00.13.10.14.00.15.00.16.00.17.00.18.00.19.00.2.00.2.10.20.00.21.00.22.00.23.00.23.10.23.20.3.00.4.00.5.00.6.00.6.10.6.20.6.30.7.00.7.10.7.20.8.00.8.20.9.00.9.1
0.24.0

History

History
RecordedChangedSources
first indexedCVE List, EUVD, GitHub Advisories, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2026-53956 is a medium vulnerability (CVSS 5.4) in Conda Py-rattler, published July 9, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.33%, the 26th percentile. Fixed in rattler_cache 0.9.0.

References

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