Unauthenticated information disclosure via exception response header
Published Mar 4, 2026 · Updated Mar 4, 2026
Information disclosure in cpp-httplib before 0.35.0 allows remote attackers to read exception messages through HTTP responses. The default catch branch in the server dispatch loop copies e.what() into the EXCEPTION_WHAT response header after escaping only carriage returns and line feeds. Exposure requires an application handler to throw without a custom exception handler; any unauthenticated client reaching that route receives internal paths, identifiers, or secrets present in the message.
Summary
What happened
Information disclosure in cpp-httplib before 0.35.0 allows remote attackers to read exception messages through HTTP responses. The default catch branch in the server dispatch loop copies e.what() into the EXCEPTION_WHAT response header after escaping only carriage returns and line feeds. Exposure requires an application handler to throw without a custom exception handler; any unauthenticated client reaching that route receives internal paths, identifiers, or secrets present in the message.
The record
- CVE
- CVE-2026-28434
- Published
- Mar 4, 2026
- Updated
- Mar 4, 2026
- Vendor
- Yuji Hirose
- Product
- cpp-httplib
- Classifications
- CWE-200, T1190
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Mar 4, 2026CVE publishedPublication date reported by the CVE source.
- Mar 4, 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?
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- Affected versionversion=< 0.35.0
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
- GHSA-8mpw-r4gc-xm7q proof-of-concept serverproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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