Security readout for executives and security teams
Plain-English summary
CVE-2026-27838 is a low-severity privacy flaw in wger. Under specific conditions, one logged-in user may see another user’s cached workout routine API response. The issue depends on the victim having already accessed the routine and a matching routine identifier being requested.
Executive priority
Treat as a routine privacy fix, not an emergency. Patch during the next normal maintenance window unless your wger instance stores sensitive employee, customer, or regulated wellness data, where faster remediation is appropriate.
Technical view
wger versions up to and including 2.4 use routine API cache keys scoped only by routine pk, not user. Five routine detail action endpoints check cache before self.get_object(), bypassing the normal ownership check when a matching cached response exists. The issue is CWE-639 insecure direct object reference.
Likely exposure
Exposure is limited to deployments of wger <= 2.4 with the affected routine API behavior enabled and caching active. Attackers require authenticated access. Confidentiality impact is limited to workout routine data; sources report no integrity or availability impact.
Exploitation context
No public source in the bundle reports active exploitation, and the CVE is not listed as KEV. Exploitation requires a logged-in attacker, a victim-cached routine response, and a matching routine identifier, which aligns with the CVSS high attack complexity rating.
Researcher notes
The core flaw is authorization bypass caused by cache lookup preceding object ownership validation. The provided sources identify five routine detail action endpoints but do not enumerate them in the bundle. Avoid assuming broader object exposure beyond routine API actions unless confirmed in code or advisory details.
Mitigation direction
- Upgrade to a wger release containing commit e964328784e2ee2830a1991d69fadbce86ac9fbf.
- If no release is available, assess applying the referenced patch per vendor guidance.
- Prioritize instances handling sensitive personal fitness or health-adjacent data.
- Review vendor advisory for deployment-specific remediation instructions.
Validation and detection
- Inventory wger deployments and identify versions up to and including 2.4.
- Confirm whether the referenced patch commit is present in deployed code.
- Review routine API caching logic for user-scoped cache keys.
- Check access logs for unusual authenticated access to routine detail API actions.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-639: Exact CWE lookup
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Open ATT&CK lookupCVE-2026-27838 mapping review
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Open ATT&CK lookup- Severity
- Low
- CVSS
- 3.1 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:N/A:N
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:N/A:N1.61.4Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
3.1LowVector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:N/A:N
Source materials
- CVE List V5 sourceCVE List V5
- https://github.com/wger-project/wger/security/advisories/GHSA-42cr-w2gr-m54qCVE reference · x_refsource_CONFIRM
- https://github.com/wger-project/wger/commit/e964328784e2ee2830a1991d69fadbce86ac9fbfCVE reference · x_refsource_MISC
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Authorization Bypass Through User-Controlled Key
Authorization Bypass Through User-Controlled Key represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.