{"api_version":"1","generated_at":"2026-10-21T20:29:17+00:00","cve":"CVE-2026-98493","urls":{"html":"https://cve.report/CVE-2026-98493","api":"https://cve.report/api/cve/CVE-2026-98493.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-98493","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-98493"},"summary":{"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.","state":"PUBLISHED","assigner":"Linux","published_at":"2026-10-18 16:17:00","updated_at":"2026-10-21 13:21:31"},"problem_types":[],"metrics":[],"references":[{"url":"https://git.kernel.org/stable/c/cbaad2922bd5d4d303055ae9afecc8999e6b40c9","name":"https://git.kernel.org/stable/c/cbaad2922bd5d4d303055ae9afecc8999e6b40c9","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/24e79508b237dd2a69bc6fb6ac5cf7f126178307","name":"https://git.kernel.org/stable/c/24e79508b237dd2a69bc6fb6ac5cf7f126178307","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/abcba6f080c63e403037ecdffde43170d242376a","name":"https://git.kernel.org/stable/c/abcba6f080c63e403037ecdffde43170d242376a","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/38a6a118260ebfc82d0c653194d616bdfbd236ac","name":"https://git.kernel.org/stable/c/38a6a118260ebfc82d0c653194d616bdfbd236ac","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/e47a1958e12abc3a17b5231a4f21c8f1bf662e08","name":"https://git.kernel.org/stable/c/e47a1958e12abc3a17b5231a4f21c8f1bf662e08","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-98493","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-98493","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 130c0f47fdf9c533deb1136cad5136f6cb7020f0 38a6a118260ebfc82d0c653194d616bdfbd236ac git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 130c0f47fdf9c533deb1136cad5136f6cb7020f0 abcba6f080c63e403037ecdffde43170d242376a git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 130c0f47fdf9c533deb1136cad5136f6cb7020f0 24e79508b237dd2a69bc6fb6ac5cf7f126178307 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 130c0f47fdf9c533deb1136cad5136f6cb7020f0 cbaad2922bd5d4d303055ae9afecc8999e6b40c9 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 130c0f47fdf9c533deb1136cad5136f6cb7020f0 e47a1958e12abc3a17b5231a4f21c8f1bf662e08 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 2.6.36","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 2.6.36 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.6.160 6.6.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.12.112 6.12.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.18.55 6.18.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.2.9 7.2.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.3 * original_commit_for_fix","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":null,"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"defaultStatus":"unaffected","product":"Linux","programFiles":["net/ipv4/ipconfig.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"38a6a118260ebfc82d0c653194d616bdfbd236ac","status":"affected","version":"130c0f47fdf9c533deb1136cad5136f6cb7020f0","versionType":"git"},{"lessThan":"abcba6f080c63e403037ecdffde43170d242376a","status":"affected","version":"130c0f47fdf9c533deb1136cad5136f6cb7020f0","versionType":"git"},{"lessThan":"24e79508b237dd2a69bc6fb6ac5cf7f126178307","status":"affected","version":"130c0f47fdf9c533deb1136cad5136f6cb7020f0","versionType":"git"},{"lessThan":"cbaad2922bd5d4d303055ae9afecc8999e6b40c9","status":"affected","version":"130c0f47fdf9c533deb1136cad5136f6cb7020f0","versionType":"git"},{"lessThan":"e47a1958e12abc3a17b5231a4f21c8f1bf662e08","status":"affected","version":"130c0f47fdf9c533deb1136cad5136f6cb7020f0","versionType":"git"}]},{"defaultStatus":"affected","product":"Linux","programFiles":["net/ipv4/ipconfig.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"status":"affected","version":"2.6.36"},{"lessThan":"2.6.36","status":"unaffected","version":"0","versionType":"semver"},{"lessThanOrEqual":"6.6.*","status":"unaffected","version":"6.6.160","versionType":"semver"},{"lessThanOrEqual":"6.12.*","status":"unaffected","version":"6.12.112","versionType":"semver"},{"lessThanOrEqual":"6.18.*","status":"unaffected","version":"6.18.55","versionType":"semver"},{"lessThanOrEqual":"7.2.*","status":"unaffected","version":"7.2.9","versionType":"semver"},{"lessThanOrEqual":"*","status":"unaffected","version":"7.3","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.6.160","versionStartIncluding":"2.6.36","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.12.112","versionStartIncluding":"2.6.36","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.18.55","versionStartIncluding":"2.6.36","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.2.9","versionStartIncluding":"2.6.36","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.3","versionStartIncluding":"2.6.36","vulnerable":true}],"negate":false,"operator":"OR"}]}],"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."}],"providerMetadata":{"dateUpdated":"2026-10-21T12:55:14.581Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"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"}],"title":"net: ipconfig: bound DHCP option construction","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-98493","datePublished":"2026-10-18T15:16:22.301Z","dateReserved":"2026-09-25T10:25:14.353Z","dateUpdated":"2026-10-21T12:55:14.581Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-10-18 16:17:00","lastModifiedDate":"2026-10-21 13:21:31","problem_types":[],"metrics":[],"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"98493","Ordinal":"1","Title":"net: ipconfig: bound DHCP option construction","CVE":"CVE-2026-98493","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"98493","Ordinal":"1","NoteData":"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.","Type":"Description","Title":"net: ipconfig: bound DHCP option construction"}]}}}