VDB-356863 · CVE-2026-40200 · EUVD-2026-21496

musl libc up to 1.2.6 control flow

CVSS Meta Temp Score CVSS is a standardized scoring system to determine possibilities of attacks. The Temp Score considers temporal factors like disclosure, exploit and countermeasures. The unique Meta Score calculates the average score of different sources to provide a normalized scoring system.	Current Exploit Price (≈) Our analysts are monitoring exploit markets and are in contact with vulnerability brokers. The range indicates the observed or calculated exploit price to be seen on exploit markets. A good indicator to understand the monetary effort required for and the popularity of an attack.	CTI Interest Score Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time. A high score indicates an elevated risk to be targeted for this vulnerability.
6.3	$0-$5k	0.14

Summaryinfo

A vulnerability has been found in musl libc up to 1.2.6 and classified as problematic. Affected by this issue is some unknown functionality. This manipulation causes control flow. This vulnerability appears as CVE-2026-40200. The attack requires local access. There is no available exploit.

Detailsinfo

A vulnerability has been found in musl libc up to 1.2.6 and classified as problematic. Affected by this vulnerability is an unknown part. The manipulation with an unknown input leads to a control flow vulnerability. The CWE definition for the vulnerability is CWE-670. The code contains a control flow path that does not reflect the algorithm that the path is intended to implement, leading to incorrect behavior any time this path is navigated. As an impact it is known to affect confidentiality, integrity, and availability. The summary by CVE is:

An issue was discovered in musl libc 0.7.10 through 1.2.6. Stack-based memory corruption can occur during qsort of very large arrays, due to incorrectly implemented double-word primitives. The number of elements must exceed about seven million, i.e., the 32nd Leonardo number on 32-bit platforms (or the 64th Leonardo number on 64-bit platforms, which is not practical).

It is possible to read the advisory at musl.libc.org. This vulnerability is known as CVE-2026-40200 since 04/10/2026. The exploitation appears to be difficult. Attacking locally is a requirement. The technical details are unknown and an exploit is not publicly available.

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2026-21496). Be aware that VulDB is the high quality source for vulnerability data.

Productinfo

Vendor

musl

Name

libc

Version

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 6.3
VulDB Meta Temp Score: 6.3

VulDB Base Score: 4.5
VulDB Temp Score: 4.5
VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA Base Score: 8.1
CNA Vector (MITRE): 🔒

CVSSv2info

AV	AC	Au	C	I	A
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Vector	Complexity	Authentication	Confidentiality	Integrity	Availability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Control flow
CWE: CWE-670
CAPEC: 🔒
ATT&CK: 🔒

Physical: Partially
Local: Yes
Remote: No

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

0-Day	Unlock	Unlock	Unlock	Unlock
Today	Unlock	Unlock	Unlock	Unlock

Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: no mitigation known
Status: 🔍

0-Day Time: 🔒

Timelineinfo

04/10/2026 Advisory disclosed
04/10/2026 +0 days CVE reserved
04/10/2026 +0 days VulDB entry created
04/10/2026 +0 days VulDB entry last update

Sourcesinfo

Advisory: musl.libc.org
Status: Not defined

CVE: CVE-2026-40200 (🔒)
GCVE (CVE): GCVE-0-2026-40200
GCVE (VulDB): GCVE-100-356863
EUVD: 🔒

Entryinfo

Created: 04/10/2026 20:16
Updated: 04/10/2026 21:55
Changes: 04/10/2026 20:16 (60), 04/10/2026 21:55 (1)
Complete: 🔍
Cache ID: 216:351:103