CVE-2025-46728: cpp-httplib is a C++ header-only HTTP/HTTPS server and client library

Q: How do I fix CVE-2025-46728?

cpp-httplib: upgrade to 0.20.1. Exact commands for each OS are on this page.

Q: Is CVE-2025-46728 being exploited?

CVE-2025-46728 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2025-46728 affect?

CVE-2025-46728 affects cpp-httplib. Severity is high (CVSS 7.5). cpp-httplib is a C++ header-only HTTP/HTTPS server and client library. Prior to version 0.20.1, the library fails to enforce configured size limits on incoming request bodies when `Transfer-Encoding: chunked` is used or when no `Content-Len

Q: How urgent is CVE-2025-46728?

Priority 49/100. High severity; Public exploit reference; Remotely exploitable, no login, no user action

This week

HIGH 7.5REMOTEUPGRADE

CVE-2025-46728 is a high-severity flaw (CVSS 7.5) affecting cpp-httplib. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

cpp-httplib is a C++ header-only HTTP/HTTPS server and client library. Prior to version 0.20.1, the library fails to enforce configured size limits on incoming request bodies when `Transfer-Encoding: chunked` is used or when no `Content-Length` header is provided. A remote attacker can send a chunked request without the terminating zero-length chunk, causing uncontrolled memory allocation on the server. This leads to potential exhaustion of syste

Why this priority

High severity
Public exploit reference
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	7.5 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.7% (top 48%)
CISA exploited list	No
Weakness	CWE-400
Published	2025-05-06
Last modified	2026-06-17

Publisher (CNA): GitHub, Inc. · Vendor: cpp-httplib project

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2025-05-06 01:15 UTCPublished CVE record published
2026-06-17 09:26 UTCUpdated Record last modified

cpp-httplib project cpp-httplib UPGRADE

Affected: < 0.20.1

Fixed in: 0.20.1

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy cpp-httplib || rpm -q cpp-httplib || cpp-httplib --version

2. UPGRADE to 0.20.1 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade cpp-httplib

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade cpp-httplib

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2025-46728?

cpp-httplib: upgrade to 0.20.1. Exact commands for each OS are on this page.

Is CVE-2025-46728 being exploited?

CVE-2025-46728 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2025-46728 affect?

CVE-2025-46728 affects cpp-httplib. Severity is high (CVSS 7.5). cpp-httplib is a C++ header-only HTTP/HTTPS server and client library. Prior to version 0.20.1, the library fails to enforce configured size limits on incoming request bodies when `Transfer-Encoding: chunked` is used or when no `Content-Len

How urgent is CVE-2025-46728?

Priority 49/100. High severity; Public exploit reference; Remotely exploitable, no login, no user action

Related CVEs

CVE-2026-54919 HIGH 7.4 UPGRADE cpp-httplib is a C++11 single-file header-only cross platform HTTP/HTTPS library
CVE-2026-45372 CRITICAL 9.9 UPGRADE cpp-httplib is a C++11 single-file header-only cross platform HTTP/HTTPS library
CVE-2026-46527 HIGH 7.5 UPGRADE cpp-httplib is a C++11 single-file header-only cross platform HTTP/HTTPS library
CVE-2026-45352 MEDIUM 5.3 UPGRADE cpp-httplib is a C++11 single-file header-only cross platform HTTP/HTTPS library
CVE-2026-33745 HIGH 7.4 UPGRADE cpp-httplib is a C++11 single-file header-only cross platform HTTP/HTTPS library

References

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