wger: IDOR via user-unscoped cache keys on routine API actions exposes workout data
Summary
Five routine detail action endpoints check a cache before calling self.get_object(). 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):
@action(detail=True)
def date_sequence_display_mode(self, request, pk=None):
cache_key = make_routine_api_date_sequence_display_cache_key(pk)
cached = cache.get(cache_key)
if cached:
return Response(cached) # returned WITHOUT calling self.get_object()
# only reaches ownership check on cache miss
routine = self.get_object()
...Cache key construction in wger/utils/cache.py:89–106:
def make_routine_api_date_sequence_display_cache_key(routine_id):
return f"routine-api-date-sequence-display-{routine_id}"
# No user ID in keyCache TTL: 1 month (4 * 604800 seconds, settings_global.py:461).
Affected endpoints:
GET /api/v2/routine/{pk}/date-sequence-display/
GET /api/v2/routine/{pk}/date-sequence-gym/
GET /api/v2/routine/{pk}/structure/
GET /api/v2/routine/{pk}/logs/
GET /api/v2/routine/{pk}/stats/PoC
1. Victim (user A) visits GET /api/v2/routine/5/structure/ → response cached under key "routine-api-structure-5"
2. Attacker (user B) visits GET /api/v2/routine/5/structure/ → cache hit → returns user A's routine structure without any ownership checkRequires 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:
def make_routine_api_date_sequence_display_cache_key(routine_id, user_id):
return f"routine-api-date-sequence-display-{user_id}-{routine_id}"Or move self.get_object() before the cache lookup so ownership is always verified first.
Affected software
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| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| Python (PyPI) | wger | <= 2.1 | no fix |
References
- https://github.com/wger-project/wger/security/advisories/GHSA-42cr-w2gr-m54q
- https://nvd.nist.gov/vuln/detail/CVE-2026-27838
- https://github.com/wger-project/wger/commit/e964328784e2ee2830a1991d69fadbce86ac9fbf
- https://github.com/wger-project/wger
- https://pypi.org/project/wger
- https://github.com/advisories/GHSA-42cr-w2gr-m54q
- CVSS vector
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:N/A:N- Weakness (CWE)
CWE-639- Platform
- Python (PyPI)
- Package
wger- Disclosed
- 26.02.2026
- Updated
- 11.10.2026 14:18
Sources and licenses
OSV / GitHub Advisory Database - PYSEC-2026-3418 - PyPA Advisory Database; CC BY 4.0
OSV / GitHub Advisory Database - GHSA-42cr-w2gr-m54q - CC BY 4.0
Vulnerability history: wger
All published vulnerabilities of this package (Python (PyPI)), newest first. Shows whether this is a one-off slip or a package that needs watching.
- Total entries
- 20
- First → latest
- 11.2022 10.2026
- Without a fix
- 16
- Exploited in attacks
- 0
Severity breakdown
- Critical 2
- High 8
- Medium 9
- Low 1
Disclosures per year
- 2022: 1
- 2023: 2
- 2024: 0
- 2025: 0
- 2026: 17
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wger: IDOR via user-unscoped cache keys on routine API actions exposes workout data this entry
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