# CVE-2026-39457

> Vulnerability · severity: **HIGH** (CVSS 7.8).

## Description

When exchanging data over a socket, libnv uses select(2) to wait for data to arrive.  However, it does not verify whether the provided socket descriptor fits in select(2)'s file descriptor set size limit of FD_SETSIZE (1024).

An attacker who is able to force a libnv application to allocate large file descriptors, e.g., by opening many descriptors and executing a program which is not careful to close them upon startup, can trigger stack corruption.  If the target application is setuid-root, then this could be used to elevate local privileges.

## Key facts

- **CVE ID:** CVE-2026-39457
- **Published:** 2026-04-30
- **CVSS severity:** HIGH
- **CVSS base score:** 7.8
- **CWE codes:** CWE-121

## Affected products

- `freebsd:freebsd`

## Primary sources

- NIST NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-39457

## Citation

> AI Analytics. CVE-2026-39457. Retrieved 2026-07-24 from https://api.ai-analytics.org/cve/CVE-2026-39457. Derived from NIST NVD. Licensed CC0.

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