CVE-2026-10640
MEDIUM 4.2Zephyr's IPv6 Neighbor Discovery send paths (net_ipv6_send_na, net_ipv6_send_ns, net_ipv6_send_rs in subsys/net/ip/ipv6_nbr.c) updated the per-interface ICMP-sent statistics by calling net_pkt_iface(pkt) after net_send_data(pkt) had already returned successfully. On the success path the network stack owns and releases the packet's reference (the L2/driver send unrefs it, e.g. ethernet_send -> net_pkt_unref), so for a freshly allocated packet with refcount 1 the net_pkt slab block can be freed before the statistics line runs (synchronously when no TX queue thread is configured, or via a concurrent TX thread otherwise). The subsequent net_pkt_iface(pkt) reads pkt->iface from the freed slab block, and with CONFIG_NET_STATISTICS_PER_INTERFACE enabled that loaded pointer is dereferenced to increment iface->stats.icmp.sent, a use-after-free (CWE-416). If the slab block was reallocated in the meantime the read/increment targets unrelated or attacker-influenced memory, yielding corrupted statistics, a fault/crash (denial of service), or potential limited memory corruption. The vulnerable Neighbor Advertisement path is reachable by any unauthenticated on-link node simply by sending ICMPv6 Neighbor Solicitations to a Zephyr node with native IPv6 enabled (handle_ns_input -> net_ipv6_send_na). Affected from v3.3.0 through v4.4.0; the fix uses the already-available iface argument instead of touching the sent packet. Configurations without per-interface statistics dereference only a global counter and are not affected by the memory-safety aspect.
No known exploitation, public exploit, or elevated probability at this time. Track for changes.
Exploitation likelihood
0.4%chance of exploitation in 30 days · 29th percentile
Impact if exploited
4.2CVSS 3.1 · MEDIUM
- ConfidentialityNone
- IntegrityLow
- AvailabilityLow
What an attacker needs
- ⚠Access: Must sit on the same / adjacent network
- ✓Privileges: No account or privileges required
- ✓User interaction: No user interaction needed
- ⚠Complexity: Needs a race window or specific setup
✓ lowers the bar for an attacker · ⚠ raises it
Proof of concept & exploit code
- reference https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-r74c-mr4m-7g9g
- github-search Search GitHub for public PoC repos
Test against your own equipment
curl -s https://vulnpedia.com/cve/CVE-2026-10640/poc.jsonMachine-readable PoC index for this CVE (for automation).Listed for defensive triage, patch verification, and authorized testing on systems you own. Machine-readable: /cve/CVE-2026-10640/poc.json
Weakness (CWE)
- CWE-416: use-after-free
CVSS vector
CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:L
Known Affected Software Configurations
| Vendor | Product | Version range |
|---|---|---|
| Zephyrproject | Zephyr | ≥ 3.3.0 and < 4.5.0 |
All CVSS metrics
- MEDIUM 4.2 v3.1 · CNA Primary
CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:L - MEDIUM 4.2 v3.1 · NVD Secondary
CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:L - HIGH 7.1 v3.1 · NVD Primary
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H