{"id":"CVE-2026-55606","aliases":["EUVD-2026-108970","GHSA-x8x4-7gvf-gp45"],"status":"published","title":"odhcpd: Stack buffer overread via DUID length endianness mismatch in memcmp()","description":"odhcpd is the DHCPv6, DHCPv4, and router-advertisement server used by OpenWrt. In versions 25.12 and prior, odhcpd's DHCPv6 self-loop detection at dhcpv6.c:720 uses a network-byte-order DUID length value directly as the memcmp() size parameter. On little-endian hosts, this causes memcmp() to read far beyond the stack buffer — a single unauthenticated DHCPv6 packet triggers a 2560-byte overread from a 128-byte buffer. At time of publication, there are no publicly available patches.","severity":{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:L","level":"medium","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-11","score":0.00466,"percentile":0.40755,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":false},"cwes":["CWE-126"],"published":"2026-10-23T13:21:21Z","modified":"2026-10-31T07:03:13Z","products":[{"vendor":"openwrt","product":"odhcpd"}],"references":[{"url":"https://github.com/openwrt/odhcpd/security/advisories/GHSA-x8x4-7gvf-gp45","tags":["x_refsource_CONFIRM","exploit","advisory"]},{"url":"https://github.com/openwrt/odhcpd/pull/401","tags":["x_refsource_MISC","fix"]},{"url":"https://github.com/openwrt/odhcpd/commit/6907f28f9ddeef9f69f5ee10bbc9ba8adc0ef57f","tags":["x_refsource_MISC","fix"]},{"url":"https://github.com/openwrt/odhcpd/commit/ed38cffa927d5fd450d20bfd3f7fb8d8e8fff301","tags":["x_refsource_MISC","fix"]},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/55xxx/CVE-2026-55606.json","tags":["advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-55606","tags":["advisory"]}],"sources":{"cve":[{"id":"CVE-2026-55606","title":"odhcpd: Stack buffer overread via DUID length endianness mismatch in memcmp()","description":"odhcpd is the DHCPv6, DHCPv4, and router-advertisement server used by OpenWrt. In versions 25.12 and prior, odhcpd's DHCPv6 self-loop detection at dhcpv6.c:720 uses a network-byte-order DUID length value directly as the memcmp() size parameter. On little-endian hosts, this causes memcmp() to read far beyond the stack buffer — a single unauthenticated DHCPv6 packet triggers a 2560-byte overread from a 128-byte buffer. At time of publication, there are no publicly available patches.","status":"published","published":"2026-10-23T13:21:21.038Z","modified":"2026-10-29T17:43:41.478Z","cvss":[{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:L","level":"medium","assessor":"cna"}],"cwes":["CWE-126"],"updated_at":"2026-11-02T14:20:11.925815Z"}],"euvd":[{"id":"EUVD-2026-108970","description":"odhcpd is the DHCPv6, DHCPv4, and router-advertisement server used by OpenWrt. In versions 25.12 and prior, odhcpd's DHCPv6 self-loop detection at dhcpv6.c:720 uses a network-byte-order DUID length value directly as the memcmp() size parameter. On little-endian hosts, this causes memcmp() to read far beyond the stack buffer — a single unauthenticated DHCPv6 packet triggers a 2560-byte overread from a 128-byte buffer. At time of publication, there are no publicly available patches.","status":"published","published":"2026-10-23T13:21:21Z","modified":"2026-10-29T17:43:41Z","cvss":[{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:L","level":"medium"}],"updated_at":"2026-11-02T16:59:15.391097Z"}],"nvd":[{"id":"CVE-2026-55606","description":"odhcpd is the DHCPv6, DHCPv4, and router-advertisement server used by OpenWrt. In versions 25.12 and prior, odhcpd's DHCPv6 self-loop detection at dhcpv6.c:720 uses a network-byte-order DUID length value directly as the memcmp() size parameter. On little-endian hosts, this causes memcmp() to read far beyond the stack buffer — a single unauthenticated DHCPv6 packet triggers a 2560-byte overread from a 128-byte buffer. At time of publication, there are no publicly available patches.","status":"published","published":"2026-10-23T14:17:53.85Z","modified":"2026-10-29T18:17:33.527Z","cvss":[{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:L","level":"medium","assessor":"secondary"}],"cwes":["CWE-126"],"updated_at":"2026-11-02T14:13:03.126833Z"}],"osv":[{"id":"CVE-2026-55606","title":"odhcpd: Stack buffer overread via DUID length endianness mismatch in memcmp()","description":"odhcpd is the DHCPv6, DHCPv4, and router-advertisement server used by OpenWrt. In versions 25.12 and prior, odhcpd's DHCPv6 self-loop detection at dhcpv6.c:720 uses a network-byte-order DUID length value directly as the memcmp() size parameter. On little-endian hosts, this causes memcmp() to read far beyond the stack buffer — a single unauthenticated DHCPv6 packet triggers a 2560-byte overread from a 128-byte buffer. At time of publication, there are no publicly available patches.","status":"published","published":"2026-10-23T13:21:21.038Z","modified":"2026-10-31T07:03:13.140581866Z","cvss":[{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:L","level":"medium"}],"cwes":["CWE-126"],"updated_at":"2026-11-02T15:45:11.22012Z"}]}}