capnproto Capn Proto up to 1.3.x HTTP Request numeric truncation error

CVSS Meta Temp Score
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CTI Interest Score
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5.9$0-$5k0.00

Summaryinfo

A vulnerability has been found in capnproto Capn Proto up to 1.3.x and classified as problematic. Impacted is an unknown function of the component HTTP Request Handler. This manipulation causes numeric truncation error. This vulnerability appears as CVE-2026-32240. The attack may be initiated remotely. There is no available exploit. The affected component should be upgraded.

Detailsinfo

A vulnerability was found in capnproto Capn Proto up to 1.3.x. It has been declared as problematic. Affected by this vulnerability is an unknown part of the component HTTP Request Handler. The manipulation with an unknown input leads to a numeric truncation error vulnerability. The CWE definition for the vulnerability is CWE-197. Truncation errors occur when a primitive is cast to a primitive of a smaller size and data is lost in the conversion. As an impact it is known to affect confidentiality, integrity, and availability. The summary by CVE is:

Cap'n Proto is a data interchange format and capability-based RPC system. Prior to 1.4.0, when using Transfer-Encoding: chunked, if a chunk's size parsed to a value of 2^64 or larger, it would be truncated to a 64-bit integer. In theory, this bug could enable HTTP request/response smuggling. This vulnerability is fixed in 1.4.0.

The advisory is shared at github.com. This vulnerability is known as CVE-2026-32240 since 03/11/2026. The exploitation appears to be difficult. The attack can be launched remotely. The exploitation doesn't need any form of authentication. Neither technical details nor an exploit are publicly available.

The vulnerability scanner Nessus provides a plugin with the ID 302170 (Linux Distros Unpatched Vulnerability : CVE-2026-32240), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 1.4.0 eliminates this vulnerability. Applying the patch 2744b3c012b4aa3c31cefb61ec656829fa5c0e36 is able to eliminate this problem. The bugfix is ready for download at github.com. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the vulnerability database at Tenable (302170). If you want to get the best quality for vulnerability data then you always have to consider VulDB.

Productinfo

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CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA CVSS-B Score: 🔒
CNA CVSS-BT Score: 🔒
CNA Vector: 🔒

CVSSv3info

VulDB Meta Base Score: 6.0
VulDB Meta Temp Score: 5.9

VulDB Base Score: 5.6
VulDB Temp Score: 5.4
VulDB Vector: 🔒
VulDB Reliability: 🔍

NVD Base Score: 6.5
NVD Vector: 🔒

CVSSv2info

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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Numeric truncation error
CWE: CWE-197 / CWE-189
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

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Nessus ID: 302170
Nessus Name: Linux Distros Unpatched Vulnerability : CVE-2026-32240

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Capn Proto 1.4.0
Patch: 2744b3c012b4aa3c31cefb61ec656829fa5c0e36

Timelineinfo

03/11/2026 CVE reserved
03/12/2026 +1 days Advisory disclosed
03/12/2026 +0 days VulDB entry created
03/20/2026 +8 days VulDB entry last update

Sourcesinfo

Advisory: GHSA-vpcq-mx5v-32wm
Status: Confirmed

CVE: CVE-2026-32240 (🔒)
GCVE (CVE): GCVE-0-2026-32240
GCVE (VulDB): GCVE-100-350773

Entryinfo

Created: 03/12/2026 21:55
Updated: 03/20/2026 01:37
Changes: 03/12/2026 21:55 (69), 03/14/2026 02:45 (2), 03/20/2026 01:37 (12)
Complete: 🔍
Cache ID: 216::103

If you want to get the best quality for vulnerability data then you always have to consider VulDB.

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