Medium · CVSS 6.3CVE-2026-5066

net: sockets: tls: Potential out-of-bounds write/read in socket_op_vtable::connect functionCVE-2026-5066

Answer in brief

CVE-2026-5066 records a Medium severity (CVSS 6.3) vulnerability in net: sockets: tls: Potential out-of-bounds write/read in socket_op_vtable::connect function. The current sources do not mark it as known exploited. The current feed maps zephyrproject-rtos/Zephyr (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Jun 4, 2026Updated Oct 15, 2026Source checked Oct 15, 2026First seen by HOL Jul 8, 2026Material review Oct 15, 2026

Upstream Advisory

Key facts

Risk: Medium · CVSS 6.3
Exploitation: Not marked as known exploited
Affected software: 1 mapped package or product
Fix availability: Available

Why this deserves its current priority

CVSS is 6.3. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps zephyrproject-rtos/Zephyr (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
zephyrproject-rtos/Zephyrgeneric	>=* <3.7.2 \|\| >=4.0.0 <4.2.2 \|\| >=4.3.0 <4.3.1	3.7.2, 4.2.2, 4.3.1

Recommended response

Check inventory. Check lockfiles and deployed manifests for zephyrproject-rtos/Zephyr.
Review the reported fix. Update zephyrproject-rtos/Zephyr to 3.7.2 if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

Published upstream
Jun 4, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Oct 15, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Jul 8, 2026

Sources and claim methodology

GitHub security advisorygithub.com

Upstream source description

A potential out-of-bounds write/read exists in the TLS socket connect path of the network sockets subsystem (subsys/net/lib/sockets/sockets_tls.c). When the TLS session cache is enabled, tls_session_store() and tls_session_restore() memcpy the caller-supplied address into a fixed-size buffer using the caller-controlled addrlen value without validating it against the destination size. struct net_sockaddr is an opaque type, so an application can pass an addrlen larger than sizeof(struct net_sockaddr) (for example 128 bytes into a 24-byte stack buffer), causing the memcpy to read and write past the end of the address memory used by the TLS session cache. This out-of-bounds write can lead to a crash and denial of service, and potentially to arbitrary code execution.

Quoted source text, attributed separately from HOL analysis.