{"cve":"CVE-2026-98493","nvd":{"published":"2026-10-18T16:17:00.257","modified":"2026-10-21T13:21:31.873","status":"Received","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.","cvss_v4":null,"cvss_v3":null,"cwes":[],"references":["https://git.kernel.org/stable/c/24e79508b237dd2a69bc6fb6ac5cf7f126178307","https://git.kernel.org/stable/c/38a6a118260ebfc82d0c653194d616bdfbd236ac","https://git.kernel.org/stable/c/abcba6f080c63e403037ecdffde43170d242376a","https://git.kernel.org/stable/c/cbaad2922bd5d4d303055ae9afecc8999e6b40c9","https://git.kernel.org/stable/c/e47a1958e12abc3a17b5231a4f21c8f1bf662e08"],"products":[],"source":"nvd","synced_at":"2026-10-22T16:41:11.231219466+00:00"},"epss":{"cve":"CVE-2026-98493","score":0.002,"percentile":0.09766,"date":"2026-10-25"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}