{"id":"CVE-2026-31423","title":"net/sched: sch_hfsc: fix divide-by-zero in rtsc_min()","summary":"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…","severity":"none","vendor":"Linux","product":"Linux","affected":["Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < ad8e8fec40290a8c8cf145c0deaadf76f80c5163","Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < ab1ff5890c7354afc7be56502fcfbd61f3b7ae4f","Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 25b6821884713a31e2b49fb67b0ebd765b33e0a9","Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < c56f78614e7781aaceca9bd3cb2128bf7d45c3bd","Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < b9e6431cbea8bb1fae8069ed099b4ee100499835","Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 17c1b9807b8a67d676b6dcf749ee932ebaa7f568","Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < d0aefec1b1a1ba2c1d251028dc2c4e5b4ce1fea5","Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 4576100b8cd03118267513cafacde164b498b322","Linux 2.6.12"],"published":"2026-04-13","updated":"2026-09-08","sourceUpdated":"2026-09-08T08:47:00.059Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-31423","references":[{"url":"https://git.kernel.org/stable/c/ad8e8fec40290a8c8cf145c0deaadf76f80c5163"},{"url":"https://git.kernel.org/stable/c/ab1ff5890c7354afc7be56502fcfbd61f3b7ae4f"},{"url":"https://git.kernel.org/stable/c/25b6821884713a31e2b49fb67b0ebd765b33e0a9"},{"url":"https://git.kernel.org/stable/c/c56f78614e7781aaceca9bd3cb2128bf7d45c3bd"},{"url":"https://git.kernel.org/stable/c/b9e6431cbea8bb1fae8069ed099b4ee100499835"},{"url":"https://git.kernel.org/stable/c/17c1b9807b8a67d676b6dcf749ee932ebaa7f568"},{"url":"https://git.kernel.org/stable/c/d0aefec1b1a1ba2c1d251028dc2c4e5b4ce1fea5"},{"url":"https://git.kernel.org/stable/c/4576100b8cd03118267513cafacde164b498b322"}],"tags":["cve.org"],"epss":0.0012,"epssPercentile":0.02114,"ingestedAt":"2026-09-08T15:33:26.991Z","slug":"CVE-2026-31423","body":"## Overview\n\nIn 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.\n\n## Affected\n\n- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < ad8e8fec40290a8c8cf145c0deaadf76f80c5163`\n- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < ab1ff5890c7354afc7be56502fcfbd61f3b7ae4f`\n- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 25b6821884713a31e2b49fb67b0ebd765b33e0a9`\n- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < c56f78614e7781aaceca9bd3cb2128bf7d45c3bd`\n- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < b9e6431cbea8bb1fae8069ed099b4ee100499835`\n- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 17c1b9807b8a67d676b6dcf749ee932ebaa7f568`\n- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < d0aefec1b1a1ba2c1d251028dc2c4e5b4ce1fea5`\n- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 4576100b8cd03118267513cafacde164b498b322`\n- `Linux 2.6.12`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":3,"depthScoreParts":{"impact":2.8,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}