SOC status:Duty analyst on shift

UK Cyber Defence
VulnerabilityAnalyzed

CVE-2026-54919

In affected Mbed TLS backend versions from 0.31.0 through 0.46.1 and wolfSSL backend versions from 0.33.0 through 0.46.1, when cpp-httplib is built with CPPHTTPLIB_MBEDTLS_SUPPORT or CPPHTTPLIB_WOLFSSL_SUPPORT and a client connects to an IP-literal host…

HIGH 7.4EPSS 0.26%

Does this matter?

High impact if exploited, but EPSS currently rates exploitation as unlikely (0.26%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.

Description

cpp-httplib is a C++11 single-file header-only cross platform HTTP/HTTPS library. In affected Mbed TLS backend versions from 0.31.0 through 0.46.1 and wolfSSL backend versions from 0.33.0 through 0.46.1, when cpp-httplib is built with CPPHTTPLIB_MBEDTLS_SUPPORT or CPPHTTPLIB_WOLFSSL_SUPPORT and a client connects to an IP-literal host with server certificate verification enabled, SSLClient and Client in HTTPS mode skip certificate chain validation and WebSocketClient on the Mbed TLS backend skips verification altogether, allowing a man-in-the-middle attacker positioned to intercept traffic to present a crafted certificate and read or modify the traffic. This issue is fixed in version 0.47.0.

CVSS 3.1
7.4 HIGHCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
EPSS
0.26% probability · 18th percentile
CISA KEV
Not listed
Weakness
CWE-295
Affected
yhirose/cpp-httplib
Source
security-advisories@github.com

Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.