CVE-2026-49991

HIGHPre-NVD 8.68.6—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 8.6 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.3%, top 81% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, secondary
Elevated
8.6
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 0%CVSS: 8.6Exploit: NoneExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

RustFS is a distributed object storage system built in Rust. In 1.0.0-beta.4, authenticated users with only PutObject permission on their own bucket can exploit a path traversal vulnerability in the Snowball auto-extract feature to write arbitrary objects into other users' buckets, completely breaking multi-tenant isolation. The vulnerability chains three flaws: No ../ sanitization in tar entry key normalization; IAM wildcard matching uses raw (uncleaned) paths; and Filesystem path cleaning resolves ../ across bucket boundaries.

CVSS v3
8.6
EG Score
8.6(medium)
EPSS
19.3%
KEV
Not listed

Published

June 26, 2026

Last Modified

June 29, 2026

Advisory Details (1)

Auto-updated Jun 26, 2026
🔬 Proof of concept available. Patch available. Sources: github.
github Patch Available🟡 PoC Available

RustFS Snowball Auto-Extract: Path Traversal allows cross-bucket object injection · Advisory · rustfs/rustfs · GitHub

https://github.com/rustfs/rustfs/security/advisories/GHSA-f4vq-9ffr-m8m3

Weakness Classification(2)

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

Data Freshness Timeline

(refreshed 24× in last 7d / 64× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. 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. Most recent first.

  1. 2026-07-15 23:31 UTCEG score recompute
  2. 2026-07-15 16:57 UTCEPSS rescore
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  1. 2026-07-08 15:16 UTCEPSS rescore
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  3. 2026-07-07 19:31 UTCEG score recompute
  4. 2026-07-07 13:46 UTCEPSS rescore
  5. 2026-07-07 08:14 UTCEG score recompute
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  7. 2026-07-06 16:27 UTCEPSS rescore
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  21. 2026-07-01 15:07 UTCEPSS rescore
  22. 2026-07-01 10:36 UTCEG score recompute
  23. 2026-06-30 23:44 UTCEG score recompute
  24. 2026-06-30 23:22 UTCEPSS rescore
  25. 2026-06-30 12:49 UTCEG score recompute
  26. 2026-06-30 01:55 UTCEG score recompute
  27. 2026-06-29 15:03 UTCEG score recompute
  28. 2026-06-29 14:06 UTCEPSS rescore
  29. 2026-06-29 14:06 UTCEPSS rescore
  30. 2026-06-29 04:11 UTCEG score recompute
  31. 2026-06-28 17:16 UTCEG score recompute
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  34. 2026-06-28 04:56 UTCEPSS rescore
  35. 2026-06-28 04:56 UTCEPSS rescore
  36. 2026-06-27 19:29 UTCEG score recompute
  37. 2026-06-27 08:37 UTCEG score recompute
  38. 2026-06-26 21:45 UTCEG score recompute
  39. 2026-06-26 21:42 UTCNVD updatefirst tracked

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Frequently asked(5)

What is CVE-2026-49991?
CVE-2026-49991 is a high vulnerability published on June 26, 2026. RustFS is a distributed object storage system built in Rust. In 1.0.0-beta.4, authenticated users with only PutObject permission on their own bucket can exploit a path traversal vulnerability in the Snowball auto-extract feature to write arbitrary objects into other users' buckets, completely…
When was CVE-2026-49991 disclosed?
CVE-2026-49991 was first published in the National Vulnerability Database on June 26, 2026, with the most recent update on June 29, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-49991 actively exploited?
CVE-2026-49991 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 19.3% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-49991?
CVE-2026-49991 has a CVSS v3 base score of 8.6 (NVD).
How do I remediate CVE-2026-49991?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-49991, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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