{"id":"CVE-2026-98493","title":"net: ipconfig: bound DHCP option construction","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet: ipconfig: bound DHCP option construction\n\nic_dhcp_init_options() appends the hostname (option 12), vendor-class\n(option 60) and client-ID (option 61) options into …","severity":"none","vendor":"Linux","product":"Linux","affected":["Linux >= 130c0f47fdf9c533deb1136cad5136f6cb7020f0 < abcba6f080c63e403037ecdffde43170d242376a","Linux >= 130c0f47fdf9c533deb1136cad5136f6cb7020f0 < 24e79508b237dd2a69bc6fb6ac5cf7f126178307","Linux >= 130c0f47fdf9c533deb1136cad5136f6cb7020f0 < cbaad2922bd5d4d303055ae9afecc8999e6b40c9","Linux >= 130c0f47fdf9c533deb1136cad5136f6cb7020f0 < e47a1958e12abc3a17b5231a4f21c8f1bf662e08","Linux 2.6.36"],"published":"2026-10-18","updated":"2026-10-18","sourceUpdated":"2026-10-18T15:16:22.301Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-98493","references":[{"url":"https://git.kernel.org/stable/c/abcba6f080c63e403037ecdffde43170d242376a"},{"url":"https://git.kernel.org/stable/c/24e79508b237dd2a69bc6fb6ac5cf7f126178307"},{"url":"https://git.kernel.org/stable/c/cbaad2922bd5d4d303055ae9afecc8999e6b40c9"},{"url":"https://git.kernel.org/stable/c/e47a1958e12abc3a17b5231a4f21c8f1bf662e08"}],"tags":["cve.org"],"ingestedAt":"2026-10-18T15:45:12.292Z","slug":"CVE-2026-98493","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nnet: ipconfig: bound DHCP option construction\n\nic_dhcp_init_options() appends the hostname (option 12), vendor-class\n(option 60) and client-ID (option 61) options into the fixed 312-byte\nbootp_pkt.exten[] buffer.  Only the client-ID branch checked the\nremaining space; the hostname and vendor-class writes were unbounded.\n\nA 64-byte hostname together with the maximum 252-byte dhcpclass=\nidentifier needs 18 + (2 + 64) + (2 + 252) = 338 of the 312 available\nbytes even before the terminating END marker, so the vendor-class memcpy\nruns past the end of exten[].  With CONFIG_FORTIFY_SOURCE this is\nreported as a field-spanning write and, when the kernel is booted with\npanic_on_warn=1, aborts boot with a panic.\n\nRoute the optional options through a common helper that makes sure the\noption, its 2-byte header and the END marker all fit and drops an option\nthat would not.  Configurations with short options keep sending exactly\nthe same bytes as before.\n\n## Affected\n\n- `Linux >= 130c0f47fdf9c533deb1136cad5136f6cb7020f0 < abcba6f080c63e403037ecdffde43170d242376a`\n- `Linux >= 130c0f47fdf9c533deb1136cad5136f6cb7020f0 < 24e79508b237dd2a69bc6fb6ac5cf7f126178307`\n- `Linux >= 130c0f47fdf9c533deb1136cad5136f6cb7020f0 < cbaad2922bd5d4d303055ae9afecc8999e6b40c9`\n- `Linux >= 130c0f47fdf9c533deb1136cad5136f6cb7020f0 < e47a1958e12abc3a17b5231a4f21c8f1bf662e08`\n- `Linux 2.6.36`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":3,"depthScoreParts":{"impact":2.8,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}