LocalS3 XML Parser Vulnerable to XML External Entity (XXE) Injection

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS 4.0

6.9 · CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N · score source

EPSS

No dated EPSS signal available.

As published by the source; long descriptions are shortened.

Description The LocalS3 project, which implements an S3-compatible storage interface, contains a critical XML External Entity (XXE) Injection vulnerability in its XML parsing functionality. When processing XML requests for multipart upload operations, the application accepts and processes XML external entities, allowing an attacker to read local system files and potentially make outbound network connections. The vulnerability exists because the XML parser is configured to process external entities and DTD (Document Type Definition) declarations without proper restrictions. This allows an attacker to define external entities that can read local files and exfiltrate their contents through outbound HTTP requests. The vulnerability is particularly severe as it allows direct access to sensitive files on the filesystem, bypassing any directory traversal protections that might be in place for normal S3 operations. Steps to Reproduce 1. Create a malicious DTD file containing the following…

Published by the source

10 Mar 2025, 18:29 UTC

Last modified by the source

10 Mar 2025, 18:29 UTC

Source last checked

26 Oct 2026, 16:35 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-47qw-ccjm-9c2c

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# Patch Next advisory brief: GHSA-47qw-ccjm-9c2c

Advisory: LocalS3 XML Parser Vulnerable to XML External Entity (XXE) Injection
IDs: GHSA-47qw-ccjm-9c2c
Record: https://patchnext.com/advisories/ghsa-47qw-ccjm-9c2c (revision 1, source checked 26 Oct 2026, 16:35 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 6.9)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: io.github.robothy:local-s3-rest 1.21. A vendor fix does not mean a deployment is fixed.

## Affected components
- Maven io.github.robothy:local-s3-rest: affected < 1.21; fixed in 1.21

## Suggested inspection (read-only)
- Maven io.github.robothy:local-s3-rest: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on io.github.robothy:local-s3-rest.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-47qw-ccjm-9c2c (GitHub-reviewed advisory GHSA-47qw-ccjm-9c2c lists affected ranges: Maven io.github.robothy:local-s3-rest >=0 <1.21)

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