ZephyrProject Zephyr up to 4.4.1 gPTP gptp_mi.c gptp_mi_qualify_announce steps_removed out-of-bounds

Summaryinfo

A vulnerability classified as critical was found in ZephyrProject Zephyr up to 4.4.1. This impacts the function gptp_mi_qualify_announce of the file subsys/net/l2/ethernet/gptp/gptp_mi.c of the component gPTP. The manipulation of the argument steps_removed results in out-of-bounds. This vulnerability is identified as CVE-2026-16514. The attack can be executed remotely. There is not any exploit available. Upgrading the affected component is advised.

Detailsinfo

A vulnerability was found in ZephyrProject Zephyr up to 4.4.1. It has been classified as critical. Affected is the function gptp_mi_qualify_announce of the file subsys/net/l2/ethernet/gptp/gptp_mi.c of the component gPTP. The manipulation of the argument steps_removed with an unknown input leads to a out-of-bounds vulnerability. CWE is classifying the issue as CWE-125. The product reads data past the end, or before the beginning, of the intended buffer. This is going to have an impact on availability. CVE summarizes:

gptp_mi_qualify_announce() in subsys/net/l2/ethernet/gptp/gptp_mi.c walks the Path Trace TLV of a received IEEE 802.1AS Announce message, comparing each clock identity against the local one. The loop bound was taken solely from the attacker-controlled wire field announce->steps_removed (accepted up to 254), never from announce->tlv.len, which is the field that states how many identities the TLV actually carries. Because path_sequence is the flexible member of the wire TLV (struct gptp_path_trace_tlv) and GPTP_ANNOUNCE() yields a raw pointer into the received packet buffer, the memcmp() inside the loop can address memory well past the end of the received frame. The stack's only length validation, GPTP_ANNOUNCE_CHECK_LEN(), requires the received gPTP payload to be exactly 68 + tlv.len bytes — so it does not constrain the loop, it guarantees the data is absent. An unauthenticated attacker on the same Ethernet segment can send a single Announce frame declaring tlv.len = 0 with steps_removed = 254; the frame passes the length check and reception path (net_gptp_recv() → gptp_handle_msg() → gptp_mi_qualify_announce()), which performs no authentication, and the loop then reads 255 entries of 8 bytes each — about 2 KB — beyond the end of the network buffer. The impact is an out-of-bounds read. The bytes read are only used as a memcmp() operand and are never returned to the attacker, so there is no meaningful information disclosure; the practical risk is that the overread crosses a network buffer pool boundary into unmapped or MPU-protected memory and faults the networking RX thread, causing a denial of service. Exposure is limited to builds that enable the opt-in, experimental CONFIG_NET_GPTP (TSN/AVB deployments) and to attackers with layer-2 adjacency, since gPTP frames are sent to a link-local multicast address and are not routed. The fix computes the true entry count as tlv.len / GPTP_CLOCK_ID_LEN and rejects the announce when steps_removed + 1 exceeds it, so the loop can no longer run past the data the packet-length check proved present.

The advisory is available at github.com. This vulnerability is traded as CVE-2026-16514 since 07/21/2026. The exploitability is told to be easy. It is possible to launch the attack remotely. The exploitation doesn't require any form of authentication. Technical details are known, but there is no available exploit.

Upgrading to version 4.4.2 eliminates this vulnerability. Applying the patch a2c882db7a57cf08a06b4d27bead22b07a9c3c61 is able to eliminate this problem. The best possible mitigation is suggested to be upgrading to the latest version.

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Productinfo

Type

• Project Management Software

Vendor

• ZephyrProject

Name

• Zephyr

Version

• 4.4.0
• 4.4.1

CPE 2.3info

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CPE 2.2info

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