SeaweedFS: Path traversal in the S3 and Iceberg REST gateways allows cross-bucket access

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No collected risk observation for these identifiers. This does not establish absence of exploitation or a zero probability.

SeaweedFS is a distributed storage system for object storage (S3), file systems, and Iceberg tables. Prior to 4.30, the S3 API gateway and the Iceberg REST catalog gateway construct their routers with mux.NewRouter().SkipClean(true). With path cleaning disabled, a .. segment inside the URL survives routing, so a request such as `GET /bucket-A/../evil-bucket/key`, is matched as bucket=bucket-A, object=../evil-bucket/key. The captured object key is then joined into a filer path with util.JoinPath (S3) / path.Join (Iceberg), which collapse the .. server-side, so the actual read or write lands in evil-bucket. This vulnerability is fixed in 4.30.

Source published

25 Jun 2026 18:41:19 UTC

Source modified

25 Jun 2026 19:05:31 UTC

Observed here

23 Oct 2026 15:48:27 UTC

Source terms

CVE Program Terms of Use

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CVSS 4.0 · 7.8 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:H/SI:H/SA:N

SeaweedFS before 4.34 contains a path traversal vulnerability in the S3 gateway DeleteMultipleObjectsHandler that allows authenticated S3 principals with write access to a single bucket to delete arbitrary objects in other tenants' buckets by supplying object keys containing ../ sequences in the DeleteObjects XML request body. Attackers can bypass authorization controls through a confused deputy condition, as the validateRequestPath middleware only inspects URL-captured path variables and never examines request-body keys, allowing the filer path to collapse directory traversal sequences and resolve deletions outside the authorized bucket.

Source published

30 Jun 2026 15:57:59 UTC

Source modified

8 Nov 2026 14:06:57 UTC

Observed here

8 Nov 2026 16:11:25 UTC

Source terms

CVE Program Terms of Use

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: cve-program · CVE Program Terms of Use. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS 3.1 · 8.1 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H

CVSS 4.0 · 7.2 CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:H/VA:H/SC:N/SI:N/SA:N

SeaweedFS is a distributed storage system for object storage (S3), file systems, and Iceberg tables. Prior to 4.30, the S3 API gateway and the Iceberg REST catalog gateway construct their routers with mux.NewRouter().SkipClean(true). With path cleaning disabled, a .. segment inside the URL survives routing, so a request such as `GET /bucket-A/../evil-bucket/key`, is matched as bucket=bucket-A, object=../evil-bucket/key. The captured object key is then joined into a filer path with util.JoinPath (S3) / path.Join (Iceberg), which collapse the .. server-side, so the actual read or write lands in evil-bucket. This vulnerability is fixed in 4.30.

Source published

Jun 25, 2026, 6:41:19 PM (timezone not stated)

Source modified

Jun 25, 2026, 7:05:31 PM (timezone not stated)

Observed here

9 Nov 2026 14:05:43 UTC

Source terms

ENISA EUVD · source terms and attribution apply

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This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: euvd · ENISA EUVD · source terms and attribution apply. Source text is retained; field grouping and change labels are provided by ChangeIntel.

EUVD CVSS 4.0 · 7.8 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:H/SI:H/SA:N

SeaweedFS before 4.34 contains a path traversal vulnerability in the S3 gateway DeleteMultipleObjectsHandler that allows authenticated S3 principals with write access to a single bucket to delete arbitrary objects in other tenants' buckets by supplying object keys containing ../ sequences in the DeleteObjects XML request body. Attackers can bypass authorization controls through a confused deputy condition, as the validateRequestPath middleware only inspects URL-captured path variables and never examines request-body keys, allowing the filer path to collapse directory traversal sequences and resolve deletions outside the authorized bucket.

Source published

Jun 30, 2026, 3:57:59 PM (timezone not stated)

Source modified

Nov 8, 2026, 2:06:57 PM (timezone not stated)

Observed here

9 Nov 2026 14:06:14 UTC

Source terms

ENISA EUVD · source terms and attribution apply

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: euvd · ENISA EUVD · source terms and attribution apply. Source text is retained; field grouping and change labels are provided by ChangeIntel.

EUVD CVSS 4.0 · 7.2 CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:H/VA:H/SC:N/SI:N/SA:N

SeaweedFS is a distributed storage system for object storage (S3), file systems, and Iceberg tables. Prior to 4.30, the S3 API gateway and the Iceberg REST catalog gateway construct their routers with mux.NewRouter().SkipClean(true). With path cleaning disabled, a .. segment inside the URL survives routing, so a request such as `GET /bucket-A/../evil-bucket/key`, is matched as bucket=bucket-A, object=../evil-bucket/key. The captured object key is then joined into a filer path with util.JoinPath (S3) / path.Join (Iceberg), which collapse the .. server-side, so the actual read or write lands in evil-bucket. This vulnerability is fixed in 4.30.

Source published

25 Jun 2026 19:16:42 UTC

Source modified

29 Jun 2026 21:21:10 UTC

Observed here

25 Oct 2026 13:17:34 UTC

Source terms

NIST NVD usage terms; underlying source attribution retained

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: nvd · NIST NVD usage terms; underlying source attribution retained. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS 4.0 · [email protected] · Secondary · 7.8 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:H/SI:H/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

CVSS 3.1 · [email protected] · Primary · 10.0 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:N

SeaweedFS before 4.34 contains a path traversal vulnerability in the S3 gateway DeleteMultipleObjectsHandler that allows authenticated S3 principals with write access to a single bucket to delete arbitrary objects in other tenants' buckets by supplying object keys containing ../ sequences in the DeleteObjects XML request body. Attackers can bypass authorization controls through a confused deputy condition, as the validateRequestPath middleware only inspects URL-captured path variables and never examines request-body keys, allowing the filer path to collapse directory traversal sequences and resolve deletions outside the authorized bucket.

Source published

30 Jun 2026 17:16:25 UTC

Source modified

8 Oct 2026 16:17:23 UTC

Observed here

25 Oct 2026 14:19:16 UTC

Source terms

NIST NVD usage terms; underlying source attribution retained

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: nvd · NIST NVD usage terms; underlying source attribution retained. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS 4.0 · [email protected] · Secondary · 7.2 CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

CVSS 3.1 · [email protected] · Secondary · 8.1 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H

## Summary The S3 API gateway and the Iceberg REST catalog gateway construct their routers with `mux.NewRouter().SkipClean(true)`. With path cleaning disabled, a `..` segment inside the URL survives routing, so a request such as: ``` GET /bucket-A/../evil-bucket/key ``` is matched as `bucket=bucket-A`, `object=../evil-bucket/key`. The captured object key is then joined into a filer path with `util.JoinPath` (S3) / `path.Join` (Iceberg), which collapse the `..` server-side, so the actual read or write lands in `evil-bucket`. The captured path variables were never validated for traversal segments before reaching the handlers, so bucket isolation depended on downstream checks rather than on the path itself. ## Impact - **With authentication disabled** (`enableAuth=false`): direct cross-bucket read and write. An object key containing `..` resolves to and operates on a different bucket than the one named in the request path. - **With authentication enabled** (`enableAuth=true`): an authorization confused-deputy. IAM evaluates the policy against the mux `{bucket}` variable (`bucket-A`) in `iam.authRequestWithAuthType`, while the I/O is performed against the traversed target (`evil-bucket`). A principal authorized for one bucket can therefore reach objects in another bucket it has no grant for. This breaks tenant isolation. The same class of traversal applies to the Iceberg REST catalog's `{prefix}`, `{namespace}`, and `{table}` path variables. `%2e%2e`-encoded and `..\` (backslash) variants are equivalent, because gorilla/mux URL-decodes captured variables and `NormalizeObjectKey` folds `\` to `/` before the path is used. ## Affected components - S3 API gateway (`weed s3`, and the S3 endpoint embedded in `weed server`) - Iceberg REST catalog gateway ## Affected versions All releases prior to **4.30**. ## Patched version **4.30** and later. ## Proof of concept With a bucket `evil-bucket` containing `secret.txt`, and a caller that only has (or needs no) access to `bucket-A`: ``` GET /bucket-A/../evil-bucket/secret.txt HTTP/1.1 Host: <gateway> ``` The response returns the contents of `evil-bucket/secret.txt`. The encoded form `GET /bucket-A/%2e%2e/evil-bucket/secret.txt` behaves identically. ## Remediation Upgrade to SeaweedFS **4.30** or later. The fix adds a validation middleware to both gateway routers that rejects any captured path variable containing a `.` or `..` segment, a NUL byte, an embedded slash/backslash in single-segment slots, or an empty captured value, before any handler runs. ## Workarounds For deployments that cannot upgrade immediately, place a reverse proxy in front of the gateway that normalizes the request path and rejects requests whose path contains `..`, `%2e%2e`, or backslash sequences. Note that disabling auth removes the only remaining barrier, so do not rely on `enableAuth=false` deployments being protected by anything. ## Resources - Fix: https://github.com/seaweedfs/seaweedfs/pull/9687 (commit `dd1b428`) ## Credits Reported responsibly by **Denis Abashkin** ([@dadbravo](https://github.com/dadbravo)).

Source published

12 Aug 2026 19:19:54 UTC

Source modified

25 Sep 2026 14:25:32 UTC

Observed here

24 Oct 2026 13:19:41 UTC

Source terms

GitHub Advisory Database · CC-BY-4.0

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: osv · GitHub Advisory Database · CC-BY-4.0. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS_V4 · CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:H/SI:H/SA:N

Publisher rating · HIGH

SeaweedFS: Path traversal in the S3 and Iceberg REST gateways allows cross-bucket access in github.com/seaweedfs/seaweedfs

Source published

18 Aug 2026 14:32:29 UTC

Source modified

25 Sep 2026 14:25:32 UTC

Observed here

24 Oct 2026 13:19:41 UTC

Source terms

OSV · upstream source license applies

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: osv · OSV · upstream source license applies. Source text is retained; field grouping and change labels are provided by ChangeIntel.