wger: IDOR via user-unscoped cache keys on routine API actions exposes workout data

Exploitation

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

CVSS

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

EPSS

• CVE-2026-27838: 0.29% estimated exploitation activity in the next 30 days; percentile 22.15 (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 Five routine detail action endpoints check a cache before calling self.getobject(). Cache keys are scoped only by pk — no user ID is included. When a victim has previously accessed their routine via the API, an attacker can retrieve the cached response for the same PK without any ownership check. Details wger/manager/api/views.py — five actions follow this pattern (lines 134–201): Cache key construction in wger/utils/cache.py:89–106: Cache TTL: 1 month (4 604800 seconds, settingsglobal.py:461). Affected endpoints: PoC Requires the victim to have previously accessed the endpoint (cache must be populated). Once populated, the cache entry is valid for 1 month. Impact An attacker with a registered account can retrieve another user's routine details — workout day sequences, exercise structure, training logs, and statistics — from cache without ownership verification. Fix: Include the user ID in the cache key: Or move self.getobject() before the cache lookup so ownership is always…

Published by the source

26 Feb 2026, 22:15 UTC

Last modified by the source

13 Jul 2026, 16:43 UTC

Source last checked

26 Oct 2026, 13:36 UTC

1. Revision 2 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-42cr-w2gr-m54q

2. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-42cr-w2gr-m54q

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# Patch Next advisory brief: CVE-2026-27838

Advisory: wger: IDOR via user-unscoped cache keys on routine API actions exposes workout data
IDs: CVE-2026-27838, GHSA-42cr-w2gr-m54q
Record: https://patchnext.com/advisories/cve-2026-27838 (revision 2, source checked 26 Oct 2026, 13:36 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Low (CVSS 3.1)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor response not established. A vendor fix does not mean a deployment is fixed.

## Affected components
- PyPI wger: affected <= 2.1

## Suggested inspection (read-only)
- `python -m pip show wger`: prints the installed version. Run with the environment that serves production active.

## Supported action
No complete vendor fix is recorded. Follow the primary source's mitigation guidance and check this record again before closing anything.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on wger.
- 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-42cr-w2gr-m54q (OSV record GHSA-42cr-w2gr-m54q lists affected ranges: PyPI wger >=0 <=2.1)
- Verified: https://github.com/advisories/GHSA-42cr-w2gr-m54q (GitHub-reviewed advisory GHSA-42cr-w2gr-m54q lists affected ranges: PyPI wger >=0 <=2.1)

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