{"id":"CVE-2026-98493","published":"2026-10-18T16:17:00.257","lastModified":"2026-10-19T10:19:01.437","description":"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 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.","cvssScore":null,"cvssSeverity":null,"cvssVector":null,"cwes":[],"vendors":[],"products":[],"references":[{"url":"https://git.kernel.org/stable/c/24e79508b237dd2a69bc6fb6ac5cf7f126178307","tags":[]},{"url":"https://git.kernel.org/stable/c/abcba6f080c63e403037ecdffde43170d242376a","tags":[]},{"url":"https://git.kernel.org/stable/c/cbaad2922bd5d4d303055ae9afecc8999e6b40c9","tags":[]},{"url":"https://git.kernel.org/stable/c/e47a1958e12abc3a17b5231a4f21c8f1bf662e08","tags":[]}],"exploitRefs":[],"hasPoc":false,"ai":null}