Out-of-bounds read in gPTP Announce path-trace validation via unvalidated stepsRemoved
Summary
| CVE | CVE-2026-16514 |
|---|---|
| State | PUBLISHED |
| Assigner | zephyr |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-09-18 15:17:05 UTC |
| Updated | 2026-09-18 19:11:57 UTC |
| Description | 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. |
Risk And Classification
Primary CVSS: v3.1 4.3 MEDIUM from [email protected]
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
EPSS: 0.002380000 probability, percentile 0.150500000 (date 2026-09-21)
Problem Types: CWE-125 | CWE-125 bounds
| Version | Source | Type | Score | Severity | Vector |
|---|---|---|---|---|---|
| 3.1 | [email protected] | Secondary | 4.3 | MEDIUM | CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L |
| 3.1 | CNA | CVSS | 4.3 | MEDIUM | CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L |
CVSS v3.1 Breakdown
Attack Vector
AdjacentAttack Complexity
LowPrivileges Required
NoneUser Interaction
NoneScope
UnchangedConfidentiality
NoneIntegrity
NoneAvailability
LowCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|---|---|---|---|
| CNA | Zephyrproject | Zephyr | affected 1.13.0 4.4.2 semver | Not specified |
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-mgxg-89rr-... | [email protected] | github.com | |
| github.com/zephyrproject-rtos/zephyr/commit/a2c882db7a57cf08a06b4d27bead... | [email protected] | github.com | |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
No vendor comments have been submitted for this CVE.
There are currently no legacy QID mappings associated with this CVE.