Low Access control exploit reference

CVE-2026-27838 — wger: IDOR via user-unscoped cache keys on routine API actions exposes workout data

wger is a free, open-source workout and fitness manager. Five routine detail action endpoints check a cache before calling `self.get_object()`. In versions up to and including 2.4, ache 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. Commit e964328784e2ee2830a1991d69fadbce86ac9fbf contains a patch for the issue.

Published Feb 26, 2026 · Updated Oct 13, 2026 · Sources: NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP · CNA: GitHub_M

Low

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

No exploitation signal in the sources consulted so far.

How the score was calculated

EPSS 0.3% (30-day exploitation probability)+2
CISA SSVC: exploitation "poc"+5

The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

Exploitation

Not confirmed

Not in CISA KEV — an absence of record, not proof it is unexploited.

EPSS FIRST

0.26%

ahead of 16% of scored CVEs · Oct 15, 2026

Affects

Wger

CVSS base

3.5

Low · 3 source(s)

CISA SSVC assessment CISA

Three decision points CISA publishes for the CVEs it assesses (SSVC 2.0.3). A stakeholder decision, not a severity score.

Exploitation

Proof of concept

none · proof-of-concept · active

Automatable

can an attacker script the kill-chain steps

Technical impact

Partial

partial · total control of the vulnerable component

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

Documented patch — github.com (NIST National Vulnerability Database)

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

Identify exposed assets running the affected vendor/product/version combinations (Wger Wger, Wger-project Wger).
Apply the fixed version or the patch documented under Remediation.
Exploitation requires user interaction: tighten email/web filtering and warn affected users.
Search available logs for exploit probes matching the vulnerability class (access control), errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

Vendor	Product	Versions	Status	Source
Wger	Wger	≤ 2.4	Vulnerable	NIST National Vulnerability Database
Wger-project	Wger	version <= 2.4	Vulnerable	CVE Program (cve.org) e CISA ADP

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Attack vector

Network

Attack complexity

Low

Privileges required

Low

User interaction

Required

Scope

Unchanged

Confidentiality

Low

Integrity

None

Availability

None

Every base score collected

Sources score independently and may disagree; each row says who scored it and under which version.

Score	Version	Severity	Expl.	Impact	Scored by
3.5	CVSS 3.1	Low	2.1	1.4	nvd@nist.gov via NIST National Vulnerability Database
3.1	CVSS 3.1	Low	1.6	1.4	security-advisories@github.com via NIST National Vulnerability Database
3.1	CVSS 3.1	Low	—	—	GitHub_M via CVE Program (cve.org) e CISA ADP

CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:N/A:N (score shown at the top: nvd@nist.gov)

Scoring entities (NIST, CNA, ADP) score independently; each score is shown with its origin. For prioritization we use 3.5 (NVD (NIST)) as a conservative provisional reference — not a definitive official score.

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-639 · Authorization Bypass Through User-Controlled Key (IDOR)

Other CVEs with this weakness →

EPSS over time FIRST

Oct 13, 2026 → Oct 15, 2026 · 3 reading(s) · max 0.26%

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

Prioritize edge telemetry for the network-reachable component (proxy, WAF, IDS/IPS).
Audit administrative actions and access to resources outside each user’s normal pattern.

web/proxy/WAF logsnetwork IDS/IPSauthentication logsapplication logs

Timeline

What happened to this CVE, newest first.

2026
Affected products added · wger-project/wger
Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
SSVC assessment updated
Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
Record published
Oct 13, 2026
Fix documented
Oct 13, 2026 · NIST National Vulnerability Database
CVSS changed · 3.5
Oct 13, 2026 · NIST National Vulnerability Database
Source status changed · → Analyzed
Oct 13, 2026 · NIST National Vulnerability Database
Record created in this database
Oct 13, 2026 · NIST National Vulnerability Database
CVE published
Feb 26, 2026 · GitHub_M

Source activity

Repeated readings are counted rather than listed.

1× Official description updated · Oct 13, 2026 – Oct 13, 2026

References

2 on the record

github.com/wger-project/wger/security/advisories/GHSA-42cr-w2gr-m54q
Exploit, Vendor Advisory, x_refsource_CONFIRM, NIST National Vulnerability Database
github.com/wger-project/wger/commit/e964328784e2ee2830a1991d69fadbce86ac9fbf
Patch, x_refsource_MISC, NIST National Vulnerability Database

Elsewhere on this site

Wger
every CVE for this vendor

Access control
same class

CWE-639
other pages naming this weakness

Related CVEs (same products)

Medium CVE-2026-45161 wger: trainer_login accepts GET - CSRF bypass enables forced session rebinding 9d
Medium CVE-2026-46438 wger: Cross-User Data Corruption via Missing Ownership Check on WorkoutLog.slot_entry 9d
Medium CVE-2026-46437 wger: API credentials remain valid after logout/password change 9d
High CVE-2026-46434 wger: Trainer Privilege Escalation - Improper Privilege Management 9d
High CVE-2026-43976 wger: cross-tenant admin notes/contracts leak via gym=None bypass (5 views) 9d
Medium CVE-2026-86256 wger before 2.6 Open Redirect via trainer-login next parameter Sep 6, 2026

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2026-27838 is "wger: IDOR via user-unscoped cache keys on routine API actions exposes workout data", rated Low. It affects Wger (Wger); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 3.5 describes technical severity. EPSS 0.26% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

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