Vulnerability · CVE-2026-34441
cpp-httplib is a C++11 single-file header-only cross platform HTTP/HTTPS library.
Published Mar 31, 2026 · catalog updated Jul 24, 2026 · cpp-httplib is a C++11
Check if you run it
No confirmed exploitation is on record for CVE-2026-34441. EPSS is 0.28%. Act only if a listed version of cpp-httplib is a C++11 is installed.
Gaps on this record
- The stored product name is a package slug. The name on this page is taken from the title (cpp-httplib is a C++11).
- No version range is stored. A customer cannot check an installed version against this record.
- No vendor fix or required action is stored. Compare the linked advisory before you change production.
- Severity
- Medium6.5
- Known exploitation
- Not in CISA/VulnCheck KEV
- EPSS
- 0.28%
- Remediation
- Advisory link
- Affected products
- cpe yhirose/cpp-httplib
cpp-httplib is a C++11 single-file header-only cross platform HTTP/HTTPS library. Prior to version 0.40.0, cpp-httplib is vulnerable to HTTP Request Smuggling. The server's static file handler serves GET responses without consuming the request body. On HTTP/1.1 keep-alive connections, the unread body bytes remain on the TCP stream and are interpreted as the start of a new HTTP request. An attacker can embed an arbitrary HTTP request inside the body of a GET request, which the server processes as a separate request. This issue has been patched in version 0.40.0.
Are you affected?
Enter the version you run. The result uses only the ranges stored on this record.
The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.
- cpe yhirose/cpp-httplibversion unspecified
How to fix CVE-2026-34441
Recommended remediation
A patch or advisory reference is linked. Open the original publisher for availability by product version.
Official advisories
What to do
Three questions, each answered from this record only. Confirm the vendor advisory before you patch.
Should you patch?
No confirmed exploitation is on record for CVE-2026-34441. EPSS is 0.28%. Act only if a listed version of cpp-httplib is a C++11 is installed.
Which versions are affected?
Affected version ranges are not on this record. Compare the installed version with the linked vendor advisory before you change production.
What should an analyst verify?
CWE-444: HTTP Request Smuggling. EPSS 0.28%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.
Code
The project this record applies to. Exploit listings stay in References.
Timeline
Detection, updates, and resolution for this record.
Mar 31, 2026 · NIST NVD
Detected
cpp-httplib is a C++11 single-file header-only cross platform HTTP/HTTPS library. Prior to version 0.40.0, cpp-httplib is vulnerable to HTTP Request Smuggling. The server's static file handler serves GET responses without consuming the request body. On HTTP/1.1 keep-alive connections, the unread body bytes remain on the TCP stream and are interpreted as the start of a new HTTP request. An attacker
Jul 24, 2026 · NIST NVD
Updated
cpp-httplib is a C++11 single-file header-only cross platform HTTP/HTTPS library. Prior to version 0.40.0, cpp-httplib is vulnerable to HTTP Request Smuggling. The server's static file handler serves GET responses without consuming the request body. On HTTP/1.1 keep-alive connections, the unread body bytes remain on the TCP stream and are interpreted as the start of a new HTTP request. An attacker
Sources
- CVE.orgVulnerability recordCVE-2026-34441
Official CVE identifier
cve.org - FIRST EPSSExploitation probabilityCVE-2026-34441
30-day exploitation probability 0.3%
first.org - NIST NVDVulnerability recordCVE-2026-34441
cpp-httplib is a C++11 single-file header-only cross platform HTTP/HTTPS library. Prior to version 0.40.0, cpp-httplib is vulnerable to HTTP Request Smuggling. The server's static file handler serves GET responses without consuming the request body. On HTTP/1.1 keep-alive connect
nvd.nist.gov
References
Freshness
Last verified in this catalog Oct 18, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.