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Fencer Intel
high 8.1

CVE-2026-43978 json

wger: Privilege escalation via trainer-login session chaining allows gym trainers to impersonate gym managers

published 5mo ago modified 4d ago also EUVD-2026-45066 , GHSA-9qpr-vc49-hqg2 , PYSEC-2026-3420

cvss
8.1
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 18%
public exploits
0
none known

Summary

wger is a free, open-source workout and fitness manager. In versions prior to 2.6, a gym trainer can escalate their session to any higher-privileged account (gym manager, general manager) by chaining two calls to the trainer-login endpoint. Once a trainer performs a legitimate switch into a low-privileged user, the session flag trainer.identity is set and this flag alone bypasses the permission check on all subsequent trainer-login calls. This grants full gym administration capabilities including viewing all member data, modifying contracts, managing gym configuration, and accessing other trainers' and managers' personal information. This issue has been fixed in version 2.6.

Patch / fix

  • wger wger 2.6

Is CVE-2026-43978 in your dependencies? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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CISA SSVC

Exploitation
Proof of concept is public
Automatable
no
Technical impact
total
Assessed
3mo ago

Exploit prediction

0.27% chance of exploitation in the next 30 days, higher than 18% of all scored CVEs (FIRST EPSS, 2026-11-09).

Exploits and checks

  • github.com https://github.com/wger-project/wger/security/advisories/GHSA-9qpr-vc49-hqg2 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 8.1 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
GitHub 3.1 8.1 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
OSV 3.1 8.1 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N

Affected packages

ecosystem package affected fixed in
pypi wger
<=2.5
 no fix listed

Affected products

  • wger-project wger

Classification

Weakness
  • CWE-269 Improper Privilege Management

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.