CKAN MCP Server: Cache-key canonicalization collision enables cache confusion / poisoning

Exploitation

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

CVSS

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

EPSS

• CVE-2026-73846: 0.19% estimated exploitation activity in the next 30 days; percentile 9.21 (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.

Summary The response cache derives its key from an ambiguous string serialization of the request parameters. canonicalizeParams joins sorted ${key}=${value} pairs with & and does not escape &, =, or the | field separators used in buildCacheKey. Two different logical parameter sets can therefore serialize to the same key and share one cache entry. Because the cached value is whatever the upstream returned for whichever request populated the entry first, an attacker can prime a colliding key so a victim's distinct query (same serverurl) is served the attacker's cached response. Affected code Confirmed collisions (identical key): - { q: "budget", rows: 10 } ≡ { q: "budget&rows=10" } → both canonicalize to q=budget&rows=10 - { filters: { a: "b" } } ≡ { filters: '{"a":"b"}' } → both canonicalize to filters={"a":"b"} (object-vs-string ambiguity) An attacker can reproduce any target canonical string by injecting it into the alphabetically-first parameter, so the collision is general, not…

Published by the source

3 Sep 2026, 14:49 UTC

Last modified by the source

3 Sep 2026, 14:49 UTC

Source last checked

26 Oct 2026, 13:02 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-78x9-fhhx-v2g6

Preview the exact text before you copy it. Commands are read-only suggestions; review them before running anything.

# Patch Next advisory brief: CVE-2026-73846

Advisory: CKAN MCP Server: Cache-key canonicalization collision enables cache confusion / poisoning
IDs: CVE-2026-73846, GHSA-78x9-fhhx-v2g6
Record: https://patchnext.com/advisories/cve-2026-73846 (revision 1, source checked 26 Oct 2026, 13:02 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 6.5)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: @aborruso/ckan-mcp-server 0.4.112. A vendor fix does not mean a deployment is fixed.

## Affected components
- npm @aborruso/ckan-mcp-server: affected < 0.4.112; fixed in 0.4.112

## Suggested inspection (read-only)
- `npm ls @aborruso/ckan-mcp-server --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 @aborruso/ckan-mcp-server.
- 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-78x9-fhhx-v2g6 (GitHub-reviewed advisory GHSA-78x9-fhhx-v2g6 lists affected ranges: npm @aborruso/ckan-mcp-server >=0 <0.4.112)

Commands are suggestions: review each one before running it.