CVE-2026-53956

MEDIUMPre-NVD 5.45.4
EchelonGraph scoreMEDIUM confidence

“—” beside the score: it is equal to the CVSS score beside it.

This medium-severity CVE scores 5.4 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.3% (24th percentile of EPSS-scored CVEs). No GitHub Security Advisory CVSS is on record for this CVE.

Triggered by: Headline CVSS from a secondary CVSS source
Sources: EPSS, a secondary CVSS source
5.4EG
EchelonGraph verdictMonitorRemediate within your standard update timelines (the SSVC decision on this page).
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0.3%CVSS: 5.4Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

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.

CVSS v3
5.4
EG Score
5.4MEDIUMmedium confidence
EG Risk
24
EG Risk 24/100

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed (value × EchelonGraph’s weight)
Severity54% × 45%
The EG Score, 5.4 of 10.
Exploitation0.3% × 40%
FIRST EPSS: the 30-day exploitation probability when EchelonGraph scored this CVE.
Automatability0% × 15%
CISA's SSVC Automatable value: no (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at every mission impact level.
Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE.
Action: A fix is available. Apply it within your standard update timelines.
EPSS PROB
0.3%
EPSS %ILE
24th
KEV
Not listed

SSVC (CISA's decision table, applied by EchelonGraph)Track at every mission impact level.

A fix is available. Apply it within your standard update timelines.

Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table

BOD 26-04 (CISA's remediation timeline, Table 1)60 days if the affected system is publicly exposed; Fix on system upgrade if it is not.

In CISA KEV no (CISA's KEV catalog) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it

Published

July 9, 2026

Last Modified

September 10, 2026

Advisory Details (1)

Auto-updated Sep 9, 2026
Patch available. Sources: github.
GitHub advisoryMentions a patch (unverified)

Package cache path traversal via conda package build string · Advisory · conda/rattler · GitHub

https://github.com/conda/rattler/security/advisories/GHSA-h672-p7h7-97v9

Vendor Advisories for CVE-2026-53956(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Affected Packages

(2 across 2 ecosystems)
crates.io(1)
PackageVulnerable rangeFix by version rangeDependents
rattler_cache—
  • every version up to 0.9.0: fixed in 0.9.0
—
PyPI(1)
PackageVulnerable rangeFix by version rangeDependents
py-rattler0.1.0 ... 0.9.1 (36 versions)
  • every version up to 0.24.0: fixed in 0.24.0
—

Weakness Classification(2)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 11× in last 7d / 34× in last 30d)

Each row is a time one of our pipelines fetched, updated or re-scored this CVE. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. An arrow marks a change the record states ("CVSS v3 → 9.1"); EPSS and GHSA rows show the values recorded at that time, not what changed (EPSS values are rounded; hover one for the exact figures). Most recent first.

  1. 2026-10-13 16:34 UTCEPSS rescoreEPSS 0.3% · 24th percentile
  2. 2026-10-12 16:34 UTCEPSS rescoreEPSS 0.3% · 24th percentile
  3. 2026-10-12 15:57 UTCEG score recompute
  4. 2026-10-11 19:40 UTCEG score recompute
  5. 2026-10-11 16:55 UTCEG score recompute
  6. 2026-10-11 14:18 UTCEG score recompute
  7. 2026-10-11 13:49 UTCEPSS rescoreEPSS 0.3% · 24th percentile
  8. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.3% · 24th percentile
  9. 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.3% · 24th percentile
  10. 2026-10-08 17:12 UTCEPSS rescoreEPSS 0.3% · 24th percentile
  11. 2026-10-07 23:48 UTCEPSS rescoreEPSS 0.3% · 24th percentile
  12. 2026-10-06 15:18 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  13. 2026-10-05 17:43 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  14. 2026-10-04 23:22 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  15. 2026-10-03 14:26 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  16. 2026-10-02 17:56 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  17. 2026-10-01 19:50 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  18. 2026-10-01 16:00 UTCEG score recompute
  19. 2026-09-30 15:03 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  20. 2026-09-29 15:22 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  21. 2026-09-28 13:51 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  22. 2026-09-28 09:56 UTCEG score recompute
  23. 2026-09-27 13:48 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  24. 2026-09-26 15:59 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  25. 2026-09-24 14:04 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
Show 21 more
  1. 2026-09-24 11:22 UTCEG score recompute
  2. 2026-09-23 17:54 UTCEPSS rescoreEPSS 0.2% · 15th percentile
  3. 2026-09-23 05:51 UTCEG score recompute
  4. 2026-09-20 20:16 UTCEPSS rescoreEPSS 0.2% · 15th percentile
  5. 2026-09-18 19:28 UTCEPSS rescoreEPSS 0.2% · 15th percentile
  6. 2026-09-18 05:26 UTCEG score recompute
  7. 2026-09-17 19:31 UTCEPSS rescoreEPSS 0.2% · 15th percentile
  8. 2026-09-16 14:08 UTCEPSS rescoreEPSS 0.2% · 15th percentile
  9. 2026-09-16 05:15 UTCEPSS rescoreEPSS 0.2% · 15th percentile
  10. 2026-09-14 07:07 UTCEG score recompute
  11. 2026-09-13 16:47 UTCEPSS rescoreEPSS 0.2% · 15th percentile
  12. 2026-09-13 08:16 UTCEG score recompute
  13. 2026-09-12 03:18 UTCEG score recompute
  14. 2026-09-11 14:53 UTCEPSS rescoreEPSS 0.2% · 15th percentile
  15. 2026-09-10 14:22 UTCEG score recompute
  16. 2026-09-10 14:00 UTCEG score recompute
  17. 2026-09-09 22:56 UTCEG score recompute
  18. 2026-07-31 07:13 UTCEG score recompute
  19. 2026-07-26 12:14 UTCEG score recompute
  20. 2026-07-23 03:19 UTCEG score recompute
  21. 2026-07-09 23:46 UTCEG score recompute

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PyPI:py-rattler

Frequently asked(5)

What is CVE-2026-53956?
CVE-2026-53956 is a medium-severity vulnerability; its CVE record was published on July 9, 2026. Rattler is a library that provides common functionality used within the conda ecosystem. rattlercache 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…
When was the CVE record for CVE-2026-53956 published?
The CVE record for CVE-2026-53956 was published on July 9, 2026. That is the record's publication date; the vulnerability itself may have been made public earlier. EchelonGraph's copy of the record carries a last-modified date of September 10, 2026; the record at its source may have been updated since.
Is CVE-2026-53956 actively exploited?
CVE-2026-53956 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.3% probability of exploitation in the next 30 days (24th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-53956?
CVE-2026-53956 has a CVSS base score of 5.4 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-53956?
A fix for CVE-2026-53956 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-53956 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

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