CVE-2026-5066
MediumCVSS 6.3Exploitation Probability (EPSS)
Low risk24th percentile - higher than 24% of all known CVEs
Summary
In the Zephyr RTOS network sockets subsystem (subsys/net/lib/sockets/sockets_tls.c), a potential out-of-bounds write/read exists in the TLS socket connect path. 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. This can lead to reading and writing past the end of the address memory, potentially causing a crash and denial of service, and possibly arbitrary code execution.
Risk Assessment
An attacker can cause a system crash or potentially execute arbitrary code, which could lead to device compromise.
Recommendation
Update Zephyr RTOS to a patched version or disable the TLS session cache.
Other vulnerabilities in Zephyr RTOS
See all- CVE-2026-13480Low
A vulnerability in the LoRaWAN TS004 Fragmented Data Block Transport handler frag_transport_package_callback() in Zephyr RTOS (subsys/lorawan/services/frag_transport.c) lacks validation of remaining payload bytes before each access. An attacker with session keys can cause an out-of-bounds read (up to ~232 bytes) past the RxPayload buffer, copying adjacent static memory into decoder buffers and the FUOTA flash image.
- CVE-2026-13213Medium
A vulnerability in the Hearing Access Service (HAS) in Zephyr RTOS allows a remote (Bluetooth) crash of the HAS peripheral. The issue occurs when a previously bonded client reconnects during the startup window before the application registers the service, leading to an assertion or NULL pointer dereference.
- CVE-2026-12633High
Vulnerability in IPv6 neighbor-discovery code (subsys/net/ip/ipv6_nbr.c) in Zephyr RTOS. The handle_ra_6co() function does not bound the context_len field from the 6CO option in Router Advertisements, leading to a buffer overflow and out-of-bounds memset. An attacker on the same link can send a crafted packet causing a system crash.
- CVE-2026-9771High
A vulnerability in the flash_copy() system call in Zephyr RTOS (with CONFIG_USERSPACE enabled) allows an unprivileged thread to pass forged pointers to flash device structures. Lack of device object validation (src_dev, dst_dev) before dereferencing enables arbitrary code execution in supervisor mode, leading to privilege escalation outside the userspace sandbox.
- CVE-2026-12364High
The vulnerability in Zephyr RTOS concerns the system-call verifier z_vrfy_z_log_msg_static_create(), which did not validate arguments passed to the kernel function. This allows an unprivileged user thread to supply arbitrary pointers and lengths, leading to kernel memory reads and system crashes.
- CVE-2026-12363Medium
The LoRaWAN Fragmented Data Block Transport service (frag_transport.c) does not validate the fragment counter in a received DATA_FRAGMENT command before forwarding it to the decoder. A frag_counter of 0 causes an underflow (frag_counter - 1), leading to an out-of-bounds write (CWE-787) in the default Semtech/LoRaMAC-node decoder, corrupting decoder state and disrupting the firmware-update (FUOTA) session.
- CVE-2026-12233Medium
The PSA Protected Storage credential backend (subsys/net/lib/tls_credentials/tls_credentials_trusted.c) declared its credential-store mutex as a plain zero-filled static struct k_mutex credential_lock; and never called k_mutex_init() on it. A statically zero-filled k_mutex has an uninitialized wait queue (its dlist head/tail are NULL instead of the self-referential sentinels that k_mutex_init/K_MUTEX_DEFINE install). The uncontended lock path does not touch the wait queue, so the defect is latent and serialized use behaves correctly.
- CVE-2026-11812Low
The vulnerability in the UpdateHub subsystem (subsys/mgmt/updatehub/updatehub.c) is due to unsynchronized access to the shared ctx structure. Concurrent operations (background autohandler and user-triggered calls) can write past the fds[1] array, overwriting adjacent struct fields, leading to internal state corruption and denial of service in the firmware update path.
- CVE-2026-10849High
The hawkBit device management client in Zephyr RTOS has a heap-based out-of-bounds write vulnerability. The response buffer lacks space for a terminating null byte, causing a single null byte write past the allocated memory when the response length matches the buffer size.
- CVE-2026-10848High
In the OCPP 1.6 client in Zephyr RTOS, a vulnerability was found involving out-of-bounds buffer read during WAMP RPC frame parsing. The extract_string_field() function uses strncpy without guaranteed null-termination, leading to reads beyond the 128-byte buffer and potential out-of-bounds null write. The vulnerability can be remotely exploited by a malicious central server or an on-path attacker.
Original NVD description (English source)
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.

