CVE-2026-49991
RustFS Snowball Auto-Extract: Path Traversal allows cross-bucket object injection
Description
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.
INFO
Published Date :
June 26, 2026, 8:17 p.m.
Last Modified :
June 29, 2026, 2:16 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 3.1 | HIGH | [email protected] |
Solution
- Sanitize tar entry keys for ../ sequences.
- Clean filesystem paths before resolving them.
- Review and restrict PutObject permissions carefully.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-49991.
| URL | Resource |
|---|---|
| https://github.com/rustfs/rustfs/security/advisories/GHSA-f4vq-9ffr-m8m3 | |
| https://github.com/rustfs/rustfs/security/advisories/GHSA-f4vq-9ffr-m8m3 |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-49991 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-49991
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-49991 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-49991 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Jun. 29, 2026
Action Type Old Value New Value Added Reference https://github.com/rustfs/rustfs/security/advisories/GHSA-f4vq-9ffr-m8m3 Added SSVC {'id': 'CVE-2026-49991', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'poc'}, {'automatable': 'yes'}, {'technicalImpact': 'partial'}], 'version': '2.0.3', 'timestamp': '2026-06-29T13:13:51.281652Z'} -
New CVE Received by [email protected]
Jun. 26, 2026
Action Type Old Value New Value Added Affected [{'vendor': 'rustfs', 'product': 'rustfs', 'versions': [{'status': 'affected', 'version': '1.0.0-beta.4'}]}] Added Description 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. Added CVSS V3.1 AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:H/A:N Added CWE CWE-22 Added CWE CWE-862 Added Reference https://github.com/rustfs/rustfs/security/advisories/GHSA-f4vq-9ffr-m8m3