CVE-2026-49991

8.6 highEPSS 0.4%

High (8.6). EPSS 0.4% chance of exploitation in the next 30 days.

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.

Severity

CVSS 3.1

8.6 high

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:H/A:N

EPSS: 0.4% chance of exploitation in the next 30 days; higher than 35% of CVEs (scores of 2026-10-31)
CWEs: CWE-22, CWE-862
Published: 2026-06-26
Modified: 2026-06-29
Record from: the NVD, synced 2026-10-19

References

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

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