CVE-2026-39457 Details
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.
A stack corruption vulnerability has been identified in the FreeBSD libnv library, which is used for exchanging name-value pairs and can facilitate Inter-Process Communication (IPC). The issue arises because libnv does not check if a socket descriptor exceeds the file descriptor set size limit of 1024 when using select() to wait for data. This oversight can be exploited by an attacker who forces a libnv application to create large file descriptors, potentially leading to stack corruption. If the affected application has setuid-root privileges, this vulnerability could be used to elevate local privileges.
Users can upgrade to a supported FreeBSD stable or release branch dated after the correction date. Instructions for updating via the FreeBSD Update utility or applying a source code patch are available in the FreeBSD Security Advisory.
Metrics
CVSS 4.0 Severity and Vector Strings:
No CVSS 4.0 data is available for this CVE.
CVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
CISA-ADP
Assessed Apr 30, 2026References to Advisories, Solutions, and Tools
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| URL | Source(s) | Tag(s) |
|---|---|---|
| https://security.freebsd.org/advisories/FreeBSD-SA-26:16.libnv.asc | [email protected] | Vendor Advisory |
Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-121 | Stack-based Buffer Overflow | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| freebsd freebsd | 13.5 - 13.5 beta3 13.5 p1 13.5 p10 13.5 p11 13.5 p12 13.5 p2 13.5 p3 13.5 p4 13.5 p5 13.5 p6 13.5 p7 13.5 p8 13.5 p9 14.3 - 14.3 p1 14.3 p10 14.3 p11 14.3 p2 14.3 p3 14.3 p4 14.3 p5 14.3 p6 14.3 p7 14.3 p8 14.3 p9 14.4 - 14.4 p1 14.4 p2 14.4 rc1 15.0 - 15.0 p1 15.0 p2 15.0 p3 15.0 p4 15.0 p5 15.0 p6 |
CPE
Remediation
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Change History
5 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Jun 17, 2026 | CVE Modified | [email protected] |
| Jun 17, 2026 | CVE Modified | CISA-ADP |
| May 1, 2026 | Initial Analysis | [email protected] |
| Apr 30, 2026 | CVE Modified | CISA-ADP |
| Apr 30, 2026 | New CVE Received | [email protected] |