🛡️ CVE-2026-31870 on Ubuntu — cpp-httplib

⚪ Unknown ✅ No Known Exploit OSV
N/A
CVSS Score
0 Low4 Medium7 High9 Critical10

Description

cpp-httplib is a C++11 single-file header-only cross platform HTTP/HTTPS library. Prior to 0.37.1, when a cpp-httplib client uses the streaming API (httplib::stream::Get, httplib::stream::Post, etc.), the library calls std::stoull() directly on the Content-Length header value received from the server with no input validation and no exception handling. std::stoull throws std::invalid_argument for non-numeric strings and std::out_of_range for values exceeding ULLONG_MAX. Since nothing catches these exceptions, the C++ runtime calls std::terminate(), which kills the process with SIGABRT. Any server the client connects to — including servers reached via HTTP redirects, third-party APIs, or man-in-the-middle positions can crash the client application with a single HTTP response. No authentication is required. No interaction from the end user is required. The crash is deterministic and immediate. This vulnerability is fixed in 0.37.1.

Distribution advisory

This page covers CVE-2026-31870 as tracked by Ubuntu, for the package cpp-httplib. No fixed version has been recorded for this distribution yet.

How this vulnerability can be exploited

This issue can be reached over the network, attack complexity is low, an attacker needs no privileges on the target. No user interaction is required. The scope is unchanged, so the impact stays within the vulnerable component. Rated impact: confidentiality none, integrity none, availability high.

Affected software and timeline

Affected software: cpp-httplib. Published on 11 March 2026 and last revised on 25 June 2026. No public exploit is currently recorded for this entry. Record sourced from OSV.

References

ubuntu.com (Report)
www.cve.org (Report)
github.com (Report)

CVE-2026-31870 on other distributions

Each distribution ships its own build and its own fixed version. Pick the one you run:

Details

Severity Unknown
CVSS Score N/A
CVSS Vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CWE N/A
Public Exploit ✅ No
Source OSV
Published 2026-03-11
Updated 2026-08-11
Modified 2026-06-25
Fix URL N/A

Affected Packages

Software From version Fixed in
cpp-httplib — —

Similar Threats

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More UBUNTU CVE 2026 advisories

Part of UBUNTU CVE 2026 in the advisory index.