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Fencer Intel
medium 4.9

CVE-2026-63329 json

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

published 4mo ago modified last mo. also EUVD-2026-84060 , GHSA-862h-v6cc-9757

Unreviewed: the maintainers' own advisory

Published by the maintainers on their GitHub repository warp-tech/warpgate. GitHub has not reviewed it into the GitHub Advisory Database, so the affected packages and versions are the maintainers' word. Read the full advisory on GitHub.

cvss
4.9
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 23%
public exploits
0
none known

Summary

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.

Patch / fix

  • warpgate_project warpgate 0.25.6

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CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
last mo.

Exploit prediction

0.31% chance of exploitation in the next 30 days, higher than 23% of all scored CVEs (FIRST EPSS, 2026-11-11).

CVSS scores

assigned by version score vector
CNA 3.1 4.9 CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:L/I:L/A:N

Affected products

  • warp-tech warpgate

Classification

Weakness
  • CWE-116 Improper Encoding or Escaping of Output
  • CWE-290 Authentication Bypass by Spoofing

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.

The maintainers of warp-tech/warpgate published their own advisory on GitHub. Reviewed sources take precedence over it.

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