{"id":"CVE-2026-31423","state":"PUBLISHED","title":"net/sched: sch_hfsc: fix divide-by-zero in rtsc_min()","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet/sched: sch_hfsc: fix divide-by-zero in rtsc_min()\n\nm2sm() converts a u32 slope to a u64 scaled value.  For large inputs\n(e.g. m1=4000000000), the result can reach 2^32.  rtsc_min() stores\nthe difference of two such u64 values in a u32 variable `dsm` and\nuses it as a divisor.  When the difference is exactly 2^32 the\ntruncation yields zero, causing a divide-by-zero oops in the\nconcave-curve intersection path:\n\n  Oops: divide error: 0000\n  RIP: 0010:rtsc_min (net/sched/sch_hfsc.c:601)\n  Call Trace:\n   init_ed (net/sched/sch_hfsc.c:629)\n   hfsc_enqueue (net/sched/sch_hfsc.c:1569)\n   [...]\n\nWiden `dsm` to u64 and replace do_div() with div64_u64() so the full\ndifference is preserved.","publishedAt":"2026-04-13T13:40:26.567Z","updatedAt":"2026-10-15T01:16:04.497Z","severity":null,"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","status":"affected","lessThan":"ad8e8fec40290a8c8cf145c0deaadf76f80c5163","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","status":"affected","lessThan":"ab1ff5890c7354afc7be56502fcfbd61f3b7ae4f","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","status":"affected","lessThan":"25b6821884713a31e2b49fb67b0ebd765b33e0a9","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","status":"affected","lessThan":"c56f78614e7781aaceca9bd3cb2128bf7d45c3bd","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","status":"affected","lessThan":"b9e6431cbea8bb1fae8069ed099b4ee100499835","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","status":"affected","lessThan":"17c1b9807b8a67d676b6dcf749ee932ebaa7f568","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","status":"affected","lessThan":"d0aefec1b1a1ba2c1d251028dc2c4e5b4ce1fea5","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","status":"affected","lessThan":"4576100b8cd03118267513cafacde164b498b322","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/sched/sch_hfsc.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"2.6.12","status":"affected"},{"version":"0","status":"unaffected","lessThan":"2.6.12","versionType":"semver"},{"version":"5.10.253","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.203","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.168","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.134","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.81","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.22","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"6.19.12","status":"unaffected","lessThanOrEqual":"6.19.*","versionType":"semver"},{"version":"7.0","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/sched/sch_hfsc.c"]}],"references":["https://git.kernel.org/stable/c/ad8e8fec40290a8c8cf145c0deaadf76f80c5163","https://git.kernel.org/stable/c/ab1ff5890c7354afc7be56502fcfbd61f3b7ae4f","https://git.kernel.org/stable/c/25b6821884713a31e2b49fb67b0ebd765b33e0a9","https://git.kernel.org/stable/c/c56f78614e7781aaceca9bd3cb2128bf7d45c3bd","https://git.kernel.org/stable/c/b9e6431cbea8bb1fae8069ed099b4ee100499835","https://git.kernel.org/stable/c/17c1b9807b8a67d676b6dcf749ee932ebaa7f568","https://git.kernel.org/stable/c/d0aefec1b1a1ba2c1d251028dc2c4e5b4ce1fea5","https://git.kernel.org/stable/c/4576100b8cd03118267513cafacde164b498b322","https://cert-portal.siemens.com/productcert/html/ssa-082556.html","https://cert-portal.siemens.com/productcert/html/ssa-019113.html","https://cert-portal.siemens.com/productcert/html/ssa-457936.html"],"weaknesses":[],"ingestedAt":"2026-10-29T20:11:40.391Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/31xxx/CVE-2026-31423.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-31423","state":"PUBLISHED","datePublished":"2026-04-13T13:40:26.567Z","dateUpdated":"2026-10-15T01:16:04.497Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-03-09T15:48:24.088Z"},"containers":{"cna":{"title":"net/sched: sch_hfsc: fix divide-by-zero in rtsc_min()","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet/sched: sch_hfsc: fix divide-by-zero in rtsc_min()\n\nm2sm() converts a u32 slope to a u64 scaled value.  For large inputs\n(e.g. m1=4000000000), the result can reach 2^32.  rtsc_min() stores\nthe difference of two such u64 values in a u32 variable `dsm` and\nuses it as a divisor.  When the difference is exactly 2^32 the\ntruncation yields zero, causing a divide-by-zero oops in the\nconcave-curve intersection path:\n\n  Oops: divide error: 0000\n  RIP: 0010:rtsc_min (net/sched/sch_hfsc.c:601)\n  Call Trace:\n   init_ed (net/sched/sch_hfsc.c:629)\n   hfsc_enqueue (net/sched/sch_hfsc.c:1569)\n   [...]\n\nWiden `dsm` to u64 and replace do_div() with div64_u64() so the full\ndifference is 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