Credential disclosure via cross-origin redirect reauthentication
Published Mar 27, 2026 · Updated Mar 27, 2026
Credential exposure in Yuji Hirose's cpp-httplib before 0.39.0 allows remote attackers to obtain credentials via cross-origin redirects. ClientImpl::setup_redirect_client copies stored authentication state to a foreign client after redirect() removes the request header, and prepare_default_headers then restores it. Exploitation requires redirect following plus configured Basic, Bearer, or Digest authentication and exposes the complete Authorization header to the redirect host.
Summary
What happened
Credential exposure in Yuji Hirose's cpp-httplib before 0.39.0 allows remote attackers to obtain credentials via cross-origin redirects. ClientImpl::setup_redirect_client copies stored authentication state to a foreign client after redirect() removes the request header, and prepare_default_headers then restores it. Exploitation requires redirect following plus configured Basic, Bearer, or Digest authentication and exposes the complete Authorization header to the redirect host.
The record
- CVE
- CVE-2026-33745
- Published
- Mar 27, 2026
- Updated
- Mar 27, 2026
- Vendor
- Yuji Hirose
- Product
- cpp-httplib
- Classifications
- CWE-200, T1557
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Mar 27, 2026CVE publishedPublication date reported by the CVE source.
- Mar 27, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=< 0.39.0
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- Cross-origin redirect credential leak proof of conceptproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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