CVE-2026-57842
Received Received - Intake

Use-After-Free and Double-Free in NetBSD COMPAT_NETBSD32

Publication date: 2026-09-11

Last updated on: 2026-09-11

Assigner: VulnCheck

Description
NetBSD contains a use-after-free and double-free vulnerability in msg_recv_copyin() within the COMPAT_NETBSD32 compatibility layer due to a missing return statement before the cleanup label on the success path. Any local user able to execute a 32-bit binary on a 64-bit NetBSD system can trigger a kernel panic or memory corruption by calling recvmsg() with msg_iovlen between 9 and IOV_MAX, causing the kernel to access a freed iovec buffer and subsequently free the same allocation a second time.

CVSS Scores

EPSS Scores

Probability:
Percentile:

Meta Information

Published
2026-09-11
Last Modified
2026-09-11
Generated
2026-09-11
AI Q&A
2026-09-11
EPSS Evaluated
N/A
NVD
CVE-2026-57842
EUVD
EUVD-2026-76106

Affected Vendors & Products

Showing 4 associated CPEs
Vendor Product Version / Range
netbsd netbsd From 8.0 (inc) to 8.3 (inc)
netbsd netbsd From 9.0 (inc) to 9.4 (inc)
netbsd netbsd From 10.0 (inc) to 10.1 (inc)
netbsd netbsd 11.0

Helpful Resources

Exploitability

CWE
CWE Icon
KEV
KEV Icon
CWE ID Description
CWE-416 The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.
CWE-415 The product calls free() twice on the same memory address.

Attack-Flow Graph

AI Quick Actions

Instant insights powered by AI
Executive Summary

CVE-2026-57842 is a use-after-free and double-free vulnerability in NetBSD's COMPAT_NETBSD32 compatibility layer. It occurs in the msg_recv_copyin() function due to a missing return statement before a cleanup label. This flaw allows local users running 32-bit binaries on 64-bit NetBSD systems to trigger kernel memory corruption or crashes by calling recvmsg() with a specific msg_iovlen value.

Detection Guidance

Detecting this vulnerability requires checking for NetBSD systems running vulnerable versions and testing the recvmsg() function with specific msg_iovlen values. Inspect the kernel version and compat32 subsystem configuration. No direct network detection commands are provided, but system logs may show kernel panics or memory corruption errors after triggering the flaw.

Impact Analysis

This vulnerability can lead to kernel memory corruption or crashes, causing system instability or denial of service. An attacker with local access could exploit it to execute arbitrary code in the kernel context, potentially gaining elevated privileges or accessing sensitive system data.

Compliance Impact

This vulnerability could potentially impact compliance with GDPR and HIPAA by enabling local privilege escalation or denial-of-service attacks on NetBSD systems. A successful exploit may lead to unauthorized memory access or system crashes, which could compromise data integrity or availability. Such incidents may violate requirements for secure processing of personal or health data under these regulations.

Mitigation Strategies

Apply the official NetBSD patch for CVE-2026-57842 by updating to a fixed kernel version. Disable the COMPAT_NETBSD32 compatibility layer if not required. Restrict local user access to execute 32-bit binaries on 64-bit systems until patched. Monitor for kernel crashes or memory corruption events as potential indicators of exploitation.

Chat Assistant

Ask questions about this CVE
Hi! I’m here to help you understand CVE-2026-57842. Ask me anything about the vulnerability, its impact, or mitigation strategies.
0/70

EPSS Chart