CVE-2026-45352

Description

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 unsigned wrap-around: strtoul("-2", …, 16) returns ULONG_MAX − 1 (0xFFFFFFFFFFFFFFFE). The library's only guard (line 12833) rejects ULONG_MAX (the result of "-1"), but any other negative value such as "-2" passes validation. The resulting near-maximum value is stored in chunk_remaining and controls how many bytes the server's read loop consumes from the network. This vulnerability is fixed in 0.43.4.

Overview

State: PUBLISHED
Assigner (CNA): GitHub_M
CVSS severity: MEDIUM
CVSS score: 5.3 / 10
CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Effective score: 5.3 / 10 MEDIUM source: CNA overview
CWE(s): CWE-20, CWE-1285, CWE-770
Reserved: 2026-05-11
Published: 2026-05-29 19:14 UTC
Last updated: 2026-06-02 01:52 UTC
Source: https://raw.githubusercontent.com/CVEProject/cvelistV5/main/cves/2026/45xxx/CVE-2026-45352.json
Linked Threat: CVE-2026-45352 — CVE-2026-45352

NVD triage scoring NVD CVE 2.0

Layer NVD adds on top of the CNA's CVE record — published / last-modified timestamps, exploitability / impact subscores, and the FIRST.org EPSS probability that this CVE will be exploited in the wild in the next 30 days.

NVD published: 2026-05-29 20:16:26 UTC
NVD last modified: 2026-07-22 06:10:00 UTC
NVD CVSS v3.1: 5.3 / 10 MEDIUM source: security-advisories@github.com
NVD CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Exploitability subscore: 3.9 / 10
Impact subscore: 1.4 / 10
EPSS score: 0.0033 (probability of exploitation in next 30 days)
EPSS percentile: 25.17% vs all CVEs — higher = more likely to be exploited, as of 2026-07-27

European Union Vulnerability Database ENISA EUVD

ENISA's official EU repository for curated vulnerability intelligence. Carries a separate identifier (EUVD-YYYY-NNNN) and frequently exposes an earlier-published description + CVSS than NVD does.

EUVD ID: EUVD-2026-33425
Assigner: GitHub_M
Published: May 29, 2026, 7:14:08 PM
Updated: Jun 2, 2026, 1:52:12 AM
EUVD base score (CVSS 3.1): 5.3 / 10
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
EUVD-reported EPSS: 0.3300
Vendors: yhirose
Products: cpp-httplib (< 0.43.4)

ENISA description: 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 unsigned wrap-around: strtoul("-2", …, 16) returns ULONG_MAX − 1 (0xFFFFFFFFFFFFFFFE). The library's only guard (line 12833) rejects ULONG_MAX (the result of "-1"), but any other negative value such as "-2" passes validation. The resulting near-maximum value is stored in chunk_remaining and controls how many bytes the server's read loop consumes from the network. This vulnerability is fixed in 0.43.4.

EUVD references (1)

https://github.com/yhirose/cpp-httplib/security/advisories/GHSA-h6wq-j5mv-f3q8

Affected products (1)

Vendor	Product	Versions	Platforms
yhirose	cpp-httplib	`< 0.43.4` (affected)	—

Affected products — CPE 2.3 (1) NVD

NVD's normalized CPE 2.3 matchers, used by vendor tools (vulnerability scanners, asset managers) for automated detection. Compare with the CNA's free-text "Affected products" section above.

cpe:2.3:a:yhirose:cpp-httplib:*:*:*:*:*:*:*:*

Vendor references (1)

References embedded in the original CVE record by the assigning CNA.

https://github.com/yhirose/cpp-httplib/security/advisories/GHSA-h6wq-j5mv-f3q8 x_refsource_CONFIRM

Web references (4)

DuckDuckGo results ranked by threat-intel / vendor advisory domains. Generated by the 🔎 Find references (web) button above — same flow as the Remediations search.

https://github.com/yhirose/cpp-httplib/security/advisories/GHSA-h6wq-j5mv-f3q8 tenable:github.com
https://nvd.nist.gov/vuln/detail/CVE-2026-45352 tenable:nvd.nist.gov
https://www.cve.org/CVERecord?id=CVE-2026-45352 tenable:www.cve.org
https://www.first.org/epss/ tenable:www.first.org

NVD-tagged references (2)

Reference list NVD curates from the CNA record, vendor advisories, and third-party reports. The tag chips below are NVD's analyst-assigned categories.

https://github.com/yhirose/cpp-httplib/security/advisories/GHSA-h6wq-j5mv-f3q8 security-advisories@github.com ExploitVendor Advisory
https://github.com/yhirose/cpp-httplib/security/advisories/GHSA-h6wq-j5mv-f3q8 134c704f-9b21-4f2e-91b3-4a467353bcc0 ExploitVendor Advisory

Remediations (16)

Remediations are stored against the linked Threat row; the list below is deduplicated across both pages.

Microsoft Patch Tuesday May 2026 - 120 Vulnerabilities Fixed, Including ...

web:cybersecuritynews.com

Microsoft's May 2026 Patch Tuesday lands with a heavy enterprise focus, fixing 120 vulnerabilities across Windows, Office, Azure, developer tools, and Microsoft 365 apps, including 29 remote code execution (RCE) flaws rated Critical.

2026-06-08 15:50 UTC
N-central third-party software patch list

web:documentation.n-able.com

N-central third-party software patch list The table below lists the third party patches available through Patch Management. The Windows agent communicates with the probe to determine what third-party applications can be updated. The agent obtains a list of applications from the probe and compares it to the software installed on a device. The agent determines what applications on a device need ...

2026-06-08 15:50 UTC
CVE-2026-45352 | Mondoo Vulnerability Intelligence

web:mondoo.com

CVE-2026-45352 - MEDIUM severity: cpp-httplib DoS: Negative chunk-size in chunked Transfer-Encoding

2026-06-08 15:50 UTC
Security Update Guide - Microsoft

web:portal.msrc.microsoft.com

The Security Update Guide provides information on the latest Microsoft security updates, helping users understand and address potential vulnerabilities effectively.

2026-06-08 15:50 UTC
About the security content of iOS 26.2 and iPadOS 26.2

web:support.apple.com

This document describes the security content of iOS 26.2 and iPadOS 26.2.

2026-06-08 15:50 UTC
Landing Page | ServiceNow Common Vulnerabilities & Exposures (CVE ...

web:support.servicenow.com

Overview The advisories below document publicly disclosed Common Vulnerabilities and Exposures ( CVEs ) in the Now Platform by ServiceNow. Because ServiceNow uses various methods to communicate vulnerability information, patches, and other fixes, customers should review family, security patch , and hotfix release notes, which are available at https://docs.servicenow.com, for a complete list of ...

2026-06-08 15:50 UTC
How To Mitigate The Microsoft Windows BitLocker YellowKey USB 0-Day

web:www.forbes.com

Following the release of a BitLocker zero-day security bypass by a disgruntled hacker, Microsoft has now offered mitigation advice until a patch is available.

2026-06-08 15:50 UTC
Oracle Critical Patch Update Advisory - April 2026

web:www.oracle.com

This Critical Patch Update contains 481 new security patches across the product families listed below. Please note that an MOS note summarizing the content of this Critical Patch Update and other Oracle Software Security Assurance activities is located at April 2026 Critical Patch Update: Executive Summary and Analysis.

2026-06-08 15:50 UTC
May 2026 Third-Party Vulnerabilities and Patches | Recast

web:www.recastsoftware.com

May 2026 third-party patch updates: key vulnerabilities, browser fixes, and critical security insights.

2026-06-08 15:50 UTC
Patch Tuesday June 2026: Security Updates & CVE Analysis

web:zecurit.com

Get the complete breakdown of Microsoft's June 2026 Patch Tuesday. We analyze the latest security updates and all critical CVEs .

2026-06-08 15:50 UTC
Security Update Guide - Microsoft Security Response Center

web:msrc.microsoft.com

Security Update Guide - Microsoft Security Response Center

2026-06-19 02:31 UTC
Oracle CPU April 2026: Delayed RUs & First Analysis ¶

web:oradba.ch

On April 21, 2026 , Oracle released the Critical Patch Update (CPU) for April 2026 — 481 new security fixes across the entire Oracle product stack. For Oracle Database, this means another round of mandatory patching. What makes this quarter unusual: several key Release Updates, including 19.31 and 23.26.2, were not available on release day and are delayed by up to a week or more.

2026-06-19 02:31 UTC
SAP Security Patch Day - February 2026

web:support.sap.com

SAP security Patch Day Bulletin

2026-06-19 02:31 UTC
March 2026 Patch Tuesday: Updates and Analysis | CrowdStrike

web:www.crowdstrike.com

Microsoft's March 2026 Patch Tuesday addresses 82 CVEs , featuring eight Critical vulnerabilities.

2026-06-19 02:31 UTC
Oracle Critical Security Patch Update Advisory - May 2026

web:www.oracle.com

This Critical Security Patch Update contains 35 new security patches across the product families listed below. Please note that an MOS note summarizing the content of this Critical Security Patch Update and other Oracle Software Security Assurance activities is located at May 2026 Critical Security Patch Update: Executive Summary and Analysis.

2026-06-19 02:31 UTC
Oracle Critical Security Patch Update June 2026 | Tenable®

web:www.tenable.com

Oracle's Critical Security Patch Update (CSPU) for June 2026 , its second CSPU, addresses 243 CVEs , including 122 critical updates.

2026-06-19 02:31 UTC

AI Forensic Analysis

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Raw JSON

The full cvelistV5 record. Download as CVE-2026-45352.json.

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