{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "extracted_events": [
              {
                "range": [
                  {
                    "introduced": "*"
                  },
                  {
                    "last_affected": "4.4.0"
                  }
                ],
                "source": "AFFECTED_FIELD",
                "strategy": "StandardRange"
              }
            ]
          },
          "events": [
            {
              "introduced": "0"
            },
            {
              "last_affected": "684c9e8f32e4373a21098559f748f06915f950c9"
            }
          ],
          "repo": "https://github.com/zephyrproject-rtos/zephyr",
          "type": "GIT"
        }
      ]
    }
  ],
  "aliases": [
    "GHSA-cvv6-5f6x-87qf"
  ],
  "database_specific": {
    "cna_assigner": "zephyr",
    "cwe_ids": [
      "CWE-125",
      "CWE-191",
      "CWE-200"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/126xxx/CVE-2026-126957.json"
  },
  "details": "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.",
  "id": "CVE-2026-126957",
  "modified": "2026-11-13T02:30:45.551265254Z",
  "published": "2026-11-12T02:23:44.385Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/126xxx/CVE-2026-126957.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-cvv6-5f6x-87qf"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-126957"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/zephyrproject-rtos/zephyr"
    }
  ],
  "schema_version": "1.9.2",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "ICMPv4 Record Route / Timestamp option: stack OOB read via ptr underflow in icmpv4.c"
}