CVE-2026-126957 - ICMPv4 Record Route / Timestamp option: stack OOB read via ptr underflow in icmpv4.c

CVE-2026-126957 - ICMPv4 Record Route / Timestamp option: stack OOB read via ptr underflow in icmpv4.c

https://cvefeed.io/rssfeed/latest.atom / Thu, 11/12/2026 - 05:08
CVE ID :CVE-2026-126957
Published : Nov. 12, 2026, 2:23 a.m. | 35 minutes ago
Description :An integer underflow in Zephyr's IPv4 option handling allows a remote, unauthenticated attacker to read stack memory. When replying to an ICMP Echo Request that carries an IPv4 Record Route or Timestamp option, icmpv4_update_record_route() and icmpv4_update_time_stamp() in subsys/net/ip/icmpv4.c compute the length of the already recorded data as ptr - ptr_offset in uint8_t arithmetic. The attacker-controlled Pointer field is checked against the option length but not against the RFC 791 minimum (4 for Record Route, 5 for Timestamp), so a smaller value wraps the length to up to 252 bytes. net_pkt_write() then reads past the 40-byte opt_data stack buffer and up to 213 bytes of stack memory, which can include stack and heap pointers, are returned in the ICMP Echo Reply. A single packet triggers the leak and the device does not crash, so it can be repeated. Devices built with CONFIG_NET_IPV4_HDR_OPTIONS, which CONFIG_NET_IPV4_IGMP selects, are affected.
Severity: 5.3 | MEDIUM
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