CVE-2026-49991

highCVSS 8.6covered by 1 sourcefirst seen 2026-06-26

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.

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Exploitation outlook

Low exploitation risk0.27% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 19% of all EPSS-scored CVEs.

Advisory coverage (1)

highCVE-2026-49991: RustFS is a distributed object storage system built in Rust. In 1.0.0-beta.4, authenticated us…nvd · 2026-06-26

External references

NVD record for CVE-2026-49991

CVE.org record

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