CVE-2026-45352: cpp-httplib is a C++11 single-file header-only cross platform HTTP/HTTPS library

Q: How do I fix CVE-2026-45352?

cpp-httplib: upgrade to 0.43.4. Exact commands for each OS are on this page.

Q: Is CVE-2026-45352 being exploited?

CVE-2026-45352 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-2026-45352 affect?

CVE-2026-45352 affects cpp-httplib. Severity is medium (CVSS 5.3). cpp-httplib is a C++11 single-file header-only cross platform HTTP/HTTPS library. Prior to 0.43.4, negative chunk-size in chunked Transfer-Encoding causes unbounded memory allocation and process crash. The ChunkedDecoder::read_payload funct

Q: How urgent is CVE-2026-45352?

Priority 35/100. Public exploit reference; Remotely exploitable, no login, no user action

This week

MEDIUM 5.3REMOTEUPGRADE

CVE-2026-45352 is a medium-severity flaw (CVSS 5.3) 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++11 single-file header-only cross platform HTTP/HTTPS library. Prior to 0.43.4, negative chunk-size in chunked Transfer-Encoding causes unbounded memory allocation and process crash. The ChunkedDecoder::read_payload function in cpp-httplib (httplib.h) parses the chunk-size field of HTTP chunked transfer encoding using std::strtoul(). Per the C standard (§7.22.1.4), strtoul silently accepts a leading minus sign, performing unsig

Why this priority

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

A fixed release or distro patch exists.

Risk facts

CVSS score	5.3 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.3% (top 74%)
CISA exploited list	No
Weakness	CWE-20, CWE-770, CWE-1285
Published	2026-05-29
Last modified	2026-07-22

Publisher (CNA): GitHub, Inc. · Vendor: yhirose

Last updated 2026-07-22 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-05-29 20:16 UTCPublished CVE record published
2026-07-22 06:10 UTCUpdated Record last modified

yhirose cpp-httplib UPGRADE

Affected: < 0.43.4

Fixed in: 0.43.4

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 0.43.4 (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-2026-45352?

cpp-httplib: upgrade to 0.43.4. Exact commands for each OS are on this page.

Is CVE-2026-45352 being exploited?

CVE-2026-45352 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-2026-45352 affect?

CVE-2026-45352 affects cpp-httplib. Severity is medium (CVSS 5.3). cpp-httplib is a C++11 single-file header-only cross platform HTTP/HTTPS library. Prior to 0.43.4, negative chunk-size in chunked Transfer-Encoding causes unbounded memory allocation and process crash. The ChunkedDecoder::read_payload funct

How urgent is CVE-2026-45352?

Priority 35/100. 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

References

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