{"id":"CVE-2026-98493","state":"PUBLISHED","title":"net: ipconfig: bound DHCP option construction","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.","publishedAt":"2026-10-18T15:16:22.301Z","updatedAt":"2026-10-30T12:38:18.516Z","severity":null,"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"130c0f47fdf9c533deb1136cad5136f6cb7020f0","status":"affected","lessThan":"e0a221cec0e0ee437680ae0314a4b166509442c5","versionType":"git"},{"version":"130c0f47fdf9c533deb1136cad5136f6cb7020f0","status":"affected","lessThan":"ca811550b9fa87e02845b4a332d194c2304d933f","versionType":"git"},{"version":"130c0f47fdf9c533deb1136cad5136f6cb7020f0","status":"affected","lessThan":"d8016c82acdd7eaa462e1f38a962b15d8c6a650b","versionType":"git"},{"version":"130c0f47fdf9c533deb1136cad5136f6cb7020f0","status":"affected","lessThan":"38a6a118260ebfc82d0c653194d616bdfbd236ac","versionType":"git"},{"version":"130c0f47fdf9c533deb1136cad5136f6cb7020f0","status":"affected","lessThan":"abcba6f080c63e403037ecdffde43170d242376a","versionType":"git"},{"version":"130c0f47fdf9c533deb1136cad5136f6cb7020f0","status":"affected","lessThan":"24e79508b237dd2a69bc6fb6ac5cf7f126178307","versionType":"git"},{"version":"130c0f47fdf9c533deb1136cad5136f6cb7020f0","status":"affected","lessThan":"cbaad2922bd5d4d303055ae9afecc8999e6b40c9","versionType":"git"},{"version":"130c0f47fdf9c533deb1136cad5136f6cb7020f0","status":"affected","lessThan":"e47a1958e12abc3a17b5231a4f21c8f1bf662e08","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/ipv4/ipconfig.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"2.6.36","status":"affected"},{"version":"0","status":"unaffected","lessThan":"2.6.36","versionType":"semver"},{"version":"5.10.273","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.224","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.191","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.160","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.112","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.55","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.9","status":"unaffected","lessThanOrEqual":"7.2.*","versionType":"semver"},{"version":"7.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/ipv4/ipconfig.c"]}],"references":["https://git.kernel.org/stable/c/e0a221cec0e0ee437680ae0314a4b166509442c5","https://git.kernel.org/stable/c/ca811550b9fa87e02845b4a332d194c2304d933f","https://git.kernel.org/stable/c/d8016c82acdd7eaa462e1f38a962b15d8c6a650b","https://git.kernel.org/stable/c/38a6a118260ebfc82d0c653194d616bdfbd236ac","https://git.kernel.org/stable/c/abcba6f080c63e403037ecdffde43170d242376a","https://git.kernel.org/stable/c/24e79508b237dd2a69bc6fb6ac5cf7f126178307","https://git.kernel.org/stable/c/cbaad2922bd5d4d303055ae9afecc8999e6b40c9","https://git.kernel.org/stable/c/e47a1958e12abc3a17b5231a4f21c8f1bf662e08"],"weaknesses":[],"ingestedAt":"2026-10-30T12:58:04.520Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/98xxx/CVE-2026-98493.json","commit":"1f312381e38164a43607eebab851b151dd16861e","baselineCommit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-98493","state":"PUBLISHED","datePublished":"2026-10-18T15:16:22.301Z","dateUpdated":"2026-10-30T12:38:18.516Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-09-25T10:25:14.353Z"},"containers":{"cna":{"title":"net: ipconfig: bound DHCP option construction","descriptions":[{"lang":"en","value":"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."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"130c0f47fdf9c533deb1136cad5136f6cb7020f0","status":"affected","lessThan":"e0a221cec0e0ee437680ae0314a4b166509442c5","versionType":"git"},{"version":"130c0f47fdf9c533deb1136cad5136f6cb7020f0","status":"affected","lessThan":"ca811550b9fa87e02845b4a332d194c2304d933f","versionType":"git"},{"version":"130c0f47fdf9c533deb1136cad5136f6cb7020f0","status":"affected","lessThan":"d8016c82acdd7eaa462e1f38a962b15d8c6a650b","versionType":"git"},{"version":"130c0f47fdf9c533deb1136cad5136f6cb7020f0","status":"affected","lessThan":"38a6a118260ebfc82d0c653194d616bdfbd236ac","versionType":"git"},{"version":"130c0f47fdf9c533deb1136cad5136f6cb7020f0","status":"affected","lessThan":"abcba6f080c63e403037ecdffde43170d242376a","versionType":"git"},{"version":"130c0f47fdf9c533deb1136cad5136f6cb7020f0","status":"affected","lessThan":"24e79508b237dd2a69bc6fb6ac5cf7f126178307","versionType":"git"},{"version":"130c0f47fdf9c533deb1136cad5136f6cb7020f0","status":"affected","lessThan":"cbaad2922bd5d4d303055ae9afecc8999e6b40c9","versionType":"git"},{"version":"130c0f47fdf9c533deb1136cad5136f6cb7020f0","status":"affected","lessThan":"e47a1958e12abc3a17b5231a4f21c8f1bf662e08","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/ipv4/ipconfig.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"2.6.36","status":"affected"},{"version":"0","status":"unaffected","lessThan":"2.6.36","versionType":"semver"},{"version":"5.10.273","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.224","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.191","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.160","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.112","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.55","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.9","status":"unaffected","lessThanOrEqual":"7.2.*","versionType":"semver"},{"version":"7.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/ipv4/ipconfig.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/e0a221cec0e0ee437680ae0314a4b166509442c5"},{"url":"https://git.kernel.org/stable/c/ca811550b9fa87e02845b4a332d194c2304d933f"},{"url":"https://git.kernel.org/stable/c/d8016c82acdd7eaa462e1f38a962b15d8c6a650b"},{"url":"https://git.kernel.org/stable/c/38a6a118260ebfc82d0c653194d616bdfbd236ac"},{"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"}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-10-30T12:38:18.516Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.36","versionEndExcluding":"5.10.273"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.36","versionEndExcluding":"5.15.224"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.36","versionEndExcluding":"6.1.191"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.36","versionEndExcluding":"6.6.160"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.36","versionEndExcluding":"6.12.112"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.36","versionEndExcluding":"6.18.55"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.36","versionEndExcluding":"7.2.9"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.36","versionEndExcluding":"7.3"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}