CVE-2026-10665 Heap buffer overflow on WireGuard receive path via unbounded incoming packet length
Remote attackers can trigger heap buffer overflow in Zephyr's WireGuard implementation via oversized packets, causing denial of service or potential code execution.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-10665?
CVE-2026-10665 is a high-severity memory corruption vulnerability in Zephyrproject Zephyr, published on 12 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
In Zephyr's WireGuard subsystem (subsys/net/lib/wireguard), wg_process_data_message() in wg_crypto.c linearizes an inbound transport-data payload into a fixed pool buffer of CONFIG_WIREGUARD_BUF_LEN bytes before decryption. The call net_buf_linearize(buf->data, data_len, pkt->buffer, ..., data_len) passed the attacker-derived data_len as both the destination capacity and the copy length, defeating the function's internal len = min(len, dst_len) bound. data_len is derived from the received UDP datagram length and is only lower-bounded by wg_ctrl_recv() (no upper bound). When data_len exceeds CONFIG_WIREGUARD_BUF_LEN — e.g. when the buffer length is lowered below the link MTU, on links with MTU above the buffer size, or via reassembled IPv4/IPv6 fragments that exceed it — the underlying memcpy writes past the end of the pool buffer, an out-of-bounds write (CWE-787). The overflow occurs before the Poly1305 authentication check, so it requires only a valid receiver session index rather than a valid authenticator, and is reachable by a malicious or compromised peer (or an on-path attacker driving an established session) over the network, yielding remote memory corruption and at minimum a reliable denial of service. The defect was present in the WireGuard implementation shipped in Zephyr 4.4.0. The fix adds an explicit data_len > CONFIG_WIREGUARD_BUF_LEN rejection and corrects the linearize call to pass net_buf_max_len(buf) as the destination capacity.
Weakness: CWE-787
Which versions are affected by CVE-2026-10665?
It affects 1 product.
Products include Zephyrproject Zephyr.
How do I fix CVE-2026-10665?
No fix has been published for CVE-2026-10665 yet. Limit exposure of the affected software until one is available.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2026-10665 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-10665 exists.
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Sources
Also known as GHSA-3wqm-wgx2-9367.