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TI-2026-26124 Aliases CVE-2026-33745

cpp-httplib Client Leaks Authentication Credentials to Untrusted Hosts on Cross-Origin HTTP Redirect

Priority HIGH 68CWE-200Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
High
Impact type
Information disclosure
Confidentiality · integrity · availability
High · High · None
Fix status
Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA. Impact type from CWE-200.

Summary

cpp-httplib is a C++11 single-file header-only cross platform HTTP/HTTPS library. Prior to 0.39.0, the cpp-httplib HTTP client forwards stored Basic Auth, Bearer Token, and Digest Auth credentials to arbitrary hosts when following cross-origin HTTP redirects (301/302/307/308). A malicious or compromised server can redirect the client to an attacker-controlled host, which then receives the plaintext credentials in the `Authorization` header. Version 0.39.0 fixes the issue.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.00266 18th percentileScored 2026-11-07
Public exploit Yes 1 exploit referenceTagged by NVD
Fix Fixed cpp-httplib (yhirose): 0.39.0

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
Poc
Automatable
No
Technical impact
Total

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
yhirosecpp-httplibbefore 0.39.00.39.0Patch availableCNA
  • cpp-httplib Vendoryhirose Affected before 0.39.0 Fixed in 0.39.0 Patch available CNA

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:yhirose:cpp-httplib:*:*:*:*:*:*:*:*before 0.39.0Vulnerableyhirose
  • cpe:2.3:a:yhirose:cpp-httplib:*:*:*:*:*:*:*:* Versions before 0.39.0 Vulnerable ·yhirose

Remediation

  • Fix · CNA cpp-httplib (yhirose) Fixed in 0.39.0

Vendor assessments

Red Hat

Red Hat's page for this CVE →

Not affected: 1 product
  • Red Hat

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-33745

References

Exploit 1

  • TI-2026-33163 cpp-httplib: HTTP header value percent-decoding in server-side `parse_header` enables CRLF injection CVSS 3.1CRITICAL 9.9
  • TI-2026-18294 cpp-httplib vulnerable to a denial of service (DOS) using a zip bomb CVSS 4.0HIGH 8.7
  • TI-2026-17313 cpp-httplib has CRLF injection in http headers CVSS 4.0HIGH 7.7
  • TI-2026-33146 cpp-httplib DoS: Negative chunk-size in chunked Transfer-Encoding CVSS 3.1HIGH 7.5
  • TI-2026-22709 Uncontrolled resource consumption in yhirose cpp-httplib CVSS 3.1HIGH 7.5
  • TI-2025-33556 cpp-httplib Unbounded Memory Allocation in Chunked/No-Length Requests Vulnerability CVSS 3.1HIGH 7.5
See all 19 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences