CVE-2026-11812
LowCVSS 2.5Exploitation Probability (EPSS)
Low risk0th percentile - higher than 0% of all known CVEs
Summary
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.
Risk Assessment
The risk includes disruption of the firmware update process, potentially preventing patch installation or causing device unavailability. The attack requires a local actor (or an unprivileged thread with CONFIG_USERSPACE) and winning a timing race, but does not lead to remote code execution.
Recommendation
Apply the vendor-provided fix that serializes entry points with a mutex and adds a bounds check to prepare_fds(). If possible, restrict access to updatehub operations to trusted users only.
Other vulnerabilities in Zephyr RTOS
See all- CVE-2026-19185High
A vulnerability was found in the system-call verifier for i3c_do_ccc() in Zephyr RTOS, which fails to validate per-target data pointers in the i3c_ccc_payload structure. The verifier also operates on the caller's live structure, allowing another thread to modify fields between check and use. This allows an unprivileged thread to write to arbitrary kernel addresses (via read CCC) or disclose kernel memory (via write CCC), leading to privilege escalation.
- CVE-2026-18747Medium
A vulnerability in the SMP-over-console transport in Zephyr RTOS allows an unauthenticated attacker to trigger a buffer length underflow by sending a single 7-byte frame to the management console. This leads to an out-of-bounds read, potentially causing a denial of service on the MCUmgr thread or memory disclosure.
- CVE-2026-18417Medium
In Zephyr RTOS, a vulnerability exists in the BSD socket layer where an asynchronous error was stored in the user_data field of the network context, which for listening TCP sockets is used to store a pointer to the parent context. In v4.3.0, after an interface-down event, the accept callback was not disarmed, leading to reuse of the poisoned value as a pointer and writes to an invalid address, causing a kernel fatal error (device crash or reset).
- CVE-2026-16513High
A vulnerability in the RTIO syscall verifier in Zephyr RTOS (before v4.3.0) allows an unprivileged user thread to write a pointer to controlled data at an arbitrary kernel address. The missing K_SYSCALL_MEMORY_WRITE check for the handle output parameter enables privilege escalation to kernel mode.
- CVE-2026-16514Medium
The gptp_mi_qualify_announce() function in Zephyr's gPTP subsystem processes received Announce messages by comparing clock identities. The comparison loop uses an attacker-controlled step count (steps_removed) instead of the actual number of TLV entries, leading to an out-of-bounds read. A single frame can cause about 2KB of overread, potentially crashing the networking RX thread and causing denial of service.
- CVE-2026-16512Low
The gptp_handle_msg() function in Zephyr RTOS does not validate the received frame length before dereferencing the gPTP header pointer. A truncated frame can lead to out-of-bounds reads, disclosing stale memory contents.
- CVE-2026-14696Medium
A vulnerability in Zephyr RTOS causes network buffer (net_pkt) leaks when Ethernet bridging is enabled (CONFIG_NET_ETHERNET_BRIDGE). Frames with unrecognized EtherType that are also delivered to the local stack are marked as NET_OK, which is interpreted as consumed, but they are never freed. An attacker on the L2 segment can flood broadcast/multicast frames with arbitrary EtherType, exhausting the RX buffer pool and causing a persistent denial of service until reboot.
- 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.
Original NVD description (English source)
The UpdateHub management subsystem (subsys/mgmt/updatehub/updatehub.c) drives every update operation through a single file-scope ctx structure that holds the CoAP block context, payload buffer, status code, socket, and a one-element poll-fd array fds[1]. Access to ctx was not serialized, and prepare_fds() wrote ctx.fds[ctx.nfds] and incremented ctx.nfds with no bounds check. Two independent paths mutate ctx concurrently: the background autohandler running on the system workqueue, and user-triggered operations reached through the updatehub run shell command, direct API calls, or — since the operations are exposed as syscalls — userspace threads. When a second flow enters prepare_fds() while ctx.nfds is already 1, the write lands one element past the array; by struct layout it overlaps the adjacent ctx.sock/ctx.nfds members. More broadly, the unsynchronized sharing lets two flows interleave connection setup and teardown, double-closing a socket descriptor or scribbling the shared buffers. The result is corruption of the update subsystem's internal state and denial of service of the firmware-update path; the out-of-bounds write is contained within the ctx structure and there is no demonstrated path to memory outside it or to code execution. Triggering requires a local actor able to invoke update operations (or, with CONFIG_USERSPACE, an unprivileged userspace thread) and to win a timing race against the background handler; remote peers cannot control the race timing. The fix serializes the entry points with a mutex and adds a bounds check to prepare_fds().
Vulnerability data from NVD (NIST) · CISA KEV · EPSS