Traffic interception via disabled certificate chain validation
Published Jul 10, 2026 · Updated Jul 10, 2026
Certificate validation bypass in cpp-httplib allows man-in-the-middle attackers to read or modify HTTPS traffic to IP-literal hosts. For affected Mbed TLS and wolfSSL builds, setup_client_tls_session disables chain verification before the handshake; Mbed TLS WebSocketClient accepts any certificate. Exploitation requires an affected backend, an IP-literal destination, enabled verification, and a network interception position; OpenSSL and DNS-hostname connections are unaffected.
Summary
What happened
Certificate validation bypass in cpp-httplib allows man-in-the-middle attackers to read or modify HTTPS traffic to IP-literal hosts. For affected Mbed TLS and wolfSSL builds, setup_client_tls_session disables chain verification before the handshake; Mbed TLS WebSocketClient accepts any certificate. Exploitation requires an affected backend, an IP-literal destination, enabled verification, and a network interception position; OpenSSL and DNS-hostname connections are unaffected.
The record
- CVE
- CVE-2026-54919
- Published
- Jul 10, 2026
- Updated
- Jul 10, 2026
- Vendor
- Yuji Hirose
- Product
- cpp-httplib
- Classifications
- CWE-295, T1557
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jul 10, 2026CVE publishedPublication date reported by the CVE source.
- Jul 10, 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=>= 0.31.0, < 0.47.0
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.
Public exploit references
No public exploit references are available in this record.
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Technologies
Your stack
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Your stack
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