repomix: attach_packed_output can bypass file-read secret scanning for supported local files

Exploitation

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

CVSS 4.0

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

EPSS

• CVE-2026-49988: 0.18% estimated exploitation activity in the next 30 days; percentile 8.00 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

attachpackedoutput can register arbitrary .json/.txt/.md/.xml files and bypass the MCP file-read safety check Summary Repomix's MCP server exposes a normal filesystemreadfile tool that reads absolute paths only after running the project's secret check. However, the attachpackedoutput plus readrepomixoutput flow can read arbitrary local .json, .txt, .md, or .xml files without the same safety check and without verifying that the file is actually a Repomix packed output. This is a medium-severity local MCP file-read boundary issue. The affected deployment is the documented repomix --mcp stdio server used by AI assistants. A prompt or lower-trust model action that can invoke MCP tools can use attachpackedoutput on a local JSON/text file, receive an outputId, then call readrepomixoutput to retrieve the full file content. Affected target - Repository: yamadashy/repomix - Commit reviewed: adf5a12f2211a7fabf24ee11a21734adccee5143 - Component: MCP server tools - Package version reviewed:…

Published by the source

1 Jul 2026, 19:01 UTC

Last modified by the source

1 Jul 2026, 19:26 UTC

Source last checked

26 Oct 2026, 12:56 UTC

1. Revision 3 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-hwpp-h97w-2h3j

2. Revision 2 · amended · 24 Oct 2026

   Reviewed OSV alias/range/CVSS4 correction; package source scopes and original publication preserved. No customer finding resolved.

3. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-hwpp-h97w-2h3j

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# Patch Next advisory brief: CVE-2026-49988

Advisory: repomix: attach_packed_output can bypass file-read secret scanning for supported local files
IDs: CVE-2026-49988, GHSA-hwpp-h97w-2h3j
Record: https://patchnext.com/advisories/cve-2026-49988 (revision 3, source checked 26 Oct 2026, 12:56 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: repomix 1.14.1. A vendor fix does not mean a deployment is fixed.

## Affected components
- npm repomix: affected <= 1.14.0; fixed in 1.14.1

## Suggested inspection (read-only)
- `npm ls repomix --all`: lists every installed copy and version, including transitive ones. Run in the project root after `npm ci`.

## 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 repomix.
- 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://osv.dev/vulnerability/GHSA-hwpp-h97w-2h3j (OSV record GHSA-hwpp-h97w-2h3j lists affected ranges: npm repomix >=0 <1.14.1 (fixed))
- Verified: https://github.com/advisories/GHSA-hwpp-h97w-2h3j (GitHub-reviewed advisory GHSA-hwpp-h97w-2h3j lists affected ranges: npm repomix >=0 <=1.14.0)

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