CVE-2026-43948: wger: cross-tenant password reset and plaintext disclosure via gym=None bypass

Should you act?

Critical, preconditions apply

Severe if exploited, but exploitation needs conditions that may not apply to you. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.

• Not in CISA KEV, but CISA’s SSVC assessment records a public proof-of-concept, so attack code exists.
• EPSS 0.4%, percentile 37: FIRST’s model estimates a 0.4% chance of exploitation activity in the next 30 days, higher than 37% of all scored CVEs (low). EPSS is a probability, not a verdict.
• Needs an account (low (any account)). Exposure depends on who can log in.
• Only applies if your dependency tree includes wger (PyPI) <= 2.5, fixed in 2.6. Check your lockfile, including transitive dependencies.

What it is

wger is a free, open-source workout and fitness manager. Prior to 2.6, the resetuserpassword and gympermissionsuseredit views in wger perform a gym-scope authorization check using Python object comparison (!=) that evaluates None != None as False, silently bypassing the guard when both the attacker and victim have no gym assignment (gym=None). A user with gym.managegym permission and gym=None can reset the password of any other gym=None user; the new plaintext password is returned verbatim in the HTML response body, enabling one-shot full account takeover. The victim's original password is invalidated, locking them out permanently. This vulnerability is fixed in 2.6.

From the GitHub advisory

Summary

The resetuserpassword and gympermissionsuseredit views in wger perform a gym-scope authorization check using Python object comparison (!=) that evaluates None != None as False, silently bypassing the guard when both the attacker and victim have no gym assignment (gym=None). A user with gym.managegym permission and gym=None can reset the password of any other gym=None user; the new plaintext password is returned verbatim in the HTML response body, enabling one-shot full account takeover. The victim's original password is invalidated, locking them out permanently.

Details

File: wger/gym/views/user.py

The authorization guard in resetuserpassword (and the parallel check in gympermissionsuseredit) uses Django ORM object comparison:

Weakness type: CWE-863.

Product: wger (PyPI) · Assigned by: GitHub_M · Published: 2026-05-12

Affected and fixed versions

Severity scores

• Attack vector: network (remotely reachable)
• Attack complexity: low
• Privileges required: low (any account)
• User interaction: none
• Scope: changed (can affect other components)

CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.

Exploitation and urgency

• CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
• CISA SSVC assessment: exploitation poc, automatable no, technical impact total.
• FIRST EPSS (model of 2026-10-21): 0.44% probability of exploitation activity in the next 30 days; percentile 37.

Timeline

• 2026-05-06 — GitHub-reviewed advisory GHSA-mhc8-p3jx-84mm published (critical)
• 2026-05-12 — CVE record published by GitHub_M
• 2026-05-13 — CVE record last updated

Sources and references

Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.

Vulnerability records

1. GitHub Advisory GHSA-mhc8-p3jx-84mm github.com
2. CVE.org record CVE-2026-43948 cve.org
3. NVD entry CVE-2026-43948 nvd.nist.gov

Other references from the CVE record and advisory

1. github.com github.com

Critical PyPI advisories · Today’s Security Digest