CVE-2026-10672 Unterminated URI buffer causes out-of-bounds read in LwM2M firmware pull (Package URI)
An attacker can trigger an out-of-bounds read in Zephyr RTOS LwM2M firmware pull, leaking adjacent memory or crashing the device.
- 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-2026-10672?
CVE-2026-10672 is a high-severity vulnerability in Zephyrproject Zephyr, published on 14 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
subsys/net/lib/lwm2m/lwm2m_pull_context.c copied the firmware-update Package URI into a fixed static buffer (context.uri, size CONFIG_LWM2M_SWMGMT_PACKAGE_URI_LEN, default 128) with memcpy(context.uri, uri, LWM2M_PACKAGE_URI_LEN), copying exactly the destination size with no length validation. The Firmware-Update object stores the server-supplied Package URI (/5/0/1) in a 255-byte buffer, so a LwM2M management server (or an on-path attacker on a session lacking strong DTLS) can WRITE a URI of 128-254 characters; only the first 128 bytes are then copied into context.uri with no NUL terminator. That buffer is subsequently consumed as a C string by http_parser_parse_url(context.uri, strlen(context.uri), ...), strlen-based CoAP URI-path/PROXY-URI option appends, and lwm2m_parse_peerinfo(), causing an out-of-bounds read of adjacent static memory. The over-read bytes are appended to outbound CoAP requests (information disclosure of adjacent device memory to the server/proxy) and can crash the device (denial of service). The vulnerable copy was introduced by the pull-context refactor (first released in v3.0.0) and is present through v4.4.0; the default-on CONFIG_LWM2M_FIRMWARE_UPDATE_PULL_SUPPORT path is affected. The fix adds a strlen(uri) >= sizeof(context.uri) check returning -ENOMEM and switches to strcpy(), guaranteeing a bounded, NUL-terminated buffer.
Weakness: CWE-125
Which versions are affected by CVE-2026-10672?
It affects 1 product.
Products include Zephyrproject Zephyr.
How do I fix CVE-2026-10672?
No fix has been published for CVE-2026-10672 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-10672 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-10672 exists.
Public exploit code: 1 proofs of concept on GitHub.
Other vulnerabilities in Zephyrproject Zephyr
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- CVE-2022-3806 Bluetooth HCI Error Handling Double Free
- CVE-2017-14199 Memory corruption in getaddrinfo
- CVE-2018-1000800 Null dereference in n/a
- CVE-2021-3329 DOS: Incorrect handling of the initial HCI ACL_MTU handshake packet leads to crash of bluetooth host layer
Sources
Also known as GHSA-rf6j-4mpp-j9mf.