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No exploitation reportedFix available

CVE-2026-18415

No exploitation reported by the sources we read.

  • Published2026-09-28
  • Fixed in4.4.2
  • WeaknessCWE-787

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

ieee802154_send() in subsys/net/l2/ieee802154/ieee802154.c copies the outgoing packet into a single fixed 125-byte transmit buffer (tx_frame_buf_pool, sized IEEE802154_MTU). In builds with CONFIG_NET_L2_IEEE802154_FRAGMENT enabled (the default whenever CONFIG_NET_6LO is set), the branch taken when 6LoWPAN fragmentation is not required performed an unchecked net_buf_add_mem(frame_buf, pkt_buf->data, pkt_buf->len). The only guard was __ASSERT_NO_MSG() inside net_buf_simple_add(), which is compiled out without CONFIG_ASSERT, so an oversized packet silently overran the frame buffer. The defect is not reachable from the radio: for NET_AF_INET6 packets ieee802154_6lo_encode_pkt() compares the whole packet length against IEEE802154_MTU and takes the fragmentation path when it does not fit, so every buffer copied on the unfragmented branch is within bounds. It is reachable through NET_AF_PACKET sockets bound to an 802.15.4 interface: for NET_SOCK_RAW the 6LoWPAN block is skipped entirely and for NET_SOCK_DGRAM it returns early on the address-family test, leaving no length validation anywhere on the transmit path (net_context_sendto() and net_if_tx() apply none, and pkt_buffer_length() does not clamp the allocation for this L2). An application — or, in a CONFIG_USERSPACE build, an unprivileged application thread using the zsock_socket()/zsock_sendto() syscalls — can therefore drive a supervisor-mode out-of-bounds write of chosen bytes past the 125-byte pool buffer. With the default CONFIG_NET_BUF_FIXED_DATA_SIZE of 128 bytes the overrun is bounded to roughly ll_hdr_len + 3 bytes; with CONFIG_NET_BUF_VARIABLE_DATA_SIZE a single storage buffer can be as large as CONFIG_NET_PKT_BUF_TX_DATA_POOL_SIZE, making the overrun far larger. The consequence is corruption of memory adjacent to the pool, with a crash or further compromise of kernel state as the practical impact. The fix validates ll_hdr_len + net_pkt_get_len(pkt) + authtag_len against IEEE802154_MTU before any copy and adds a tailroom-checking copy_pkt_to_frame() helper that returns -EMSGSIZE instead of overrunning the buffer. The same change also linearizes the whole net_buf chain into one MAC frame, so packet storage boundaries no longer become frame boundaries on the wire.

Timeline

dates in UTC
  1. 2026-09-2821:17CVE publishedNVD

Observed activity

isMalicious corpus · updated 2026-10-28 09:37 UTC
Indicators tagged with this CVE, per day0 indicators over 7 days
Block these indicators
  • Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2026-18415?format=txt
  • CSV export: https://api.ismalicious.com/edl/cve/CVE-2026-18415?format=csv
  • TAXII collection of exploited CVEs
  • The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD
Zephyrproject zephyr
BranchAffectedFixed in
4.4≥ 3.2.0, < 4.4.24.4.2

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Fix

  1. Update Zephyrproject zephyr to 4.4.2

Advisories and patches

Detection

Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof-of-concept repositories
none listed
PoC-in-GitHub

Sources

  • CISA-ADPSSVC decisionnone2026-09-30
  • OpenCVESSVC decisionnone—
  • CNACVSS 3.16.3read 2026-10-28
  • NVDCVSS 3.17.1read 2026-10-28
  • CNAweakness (CWE)CWE-787read 2026-10-28
  • FIRST EPSSEPSS score0.10 %2026-10-26

Technical details

CVSS v3 Vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H
Published
2026-09-28
Last Modified
2026-10-27
NVD status
Analyzed

Frequently asked questions

What is CVE-2026-18415?

ieee802154_send() in subsys/net/l2/ieee802154/ieee802154.c copies the outgoing packet into a single fixed 125-byte transmit buffer (tx_frame_buf_pool, sized IEEE802154_MTU). In builds with CONFIG_NET_L2_IEEE802154_FRAGMENT enabled (the default whenever CONFIG_NET_6LO is set), the branch taken when 6LoWPAN fragmentation is not required performed an unchecked net_buf_add_mem(frame_buf, pkt_buf->data, pkt_buf->len). The only guard was __ASSERT_NO_MSG() inside net_buf_simple_add(), which is compiled out without CONFIG_ASSERT, so an oversized packet silently overran the frame buffer. The defect is not reachable from the radio: for NET_AF_INET6 packets ieee802154_6lo_encode_pkt() compares the whole packet length against IEEE802154_MTU and takes the fragmentation path when it does not fit, so every buffer copied on the unfragmented branch is within bounds. It is reachable through NET_AF_PACKET sockets bound to an 802.15.4 interface: for NET_SOCK_RAW the 6LoWPAN block is skipped entirely and for NET_SOCK_DGRAM it returns early on the address-family test, leaving no length validation anywhere on the transmit path (net_context_sendto() and net_if_tx() apply none, and pkt_buffer_length() does not clamp the allocation for this L2). An application — or, in a CONFIG_USERSPACE build, an unprivileged application thread using the zsock_socket()/zsock_sendto() syscalls — can therefore drive a supervisor-mode out-of-bounds write of chosen bytes past the 125-byte pool buffer. With the default CONFIG_NET_BUF_FIXED_DATA_SIZE of 128 bytes the overrun is bounded to roughly ll_hdr_len + 3 bytes; with CONFIG_NET_BUF_VARIABLE_DATA_SIZE a single storage buffer can be as large as CONFIG_NET_PKT_BUF_TX_DATA_POOL_SIZE, making the overrun far larger. The consequence is corruption of memory adjacent to the pool, with a crash or further compromise of kernel state as the practical impact. The fix validates ll_hdr_len + net_pkt_get_len(pkt) + authtag_len against IEEE802154_MTU before any copy and adds a tailroom-checking copy_pkt_to_frame() helper that returns -EMSGSIZE instead of overrunning the buffer. The same change also linearizes the whole net_buf chain into one MAC frame, so packet storage boundaries no longer become frame boundaries on the wire.

Is CVE-2026-18415 actively exploited?

Active exploitation of CVE-2026-18415 has not been confirmed. Its EPSS score was 0.10% on 2026-10-26, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2026-18415?

CVE-2026-18415 has a CVSS v3 base score of 7.1 (HIGH severity), with vector string CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H.

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