Answer in brief
CVE-2026-31423 records a Medium severity (CVSS 5.5) vulnerability in net/sched: sch_hfsc: fix divide-by-zero in rtsc_min(). The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic), Linux/Linux (generic), Siemens/SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (generic), Siemens/SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (generic) and additional mapped packages. Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
Answer in brief
CVE-2026-31423 records a Medium severity (CVSS 5.5) vulnerability in net/sched: sch_hfsc: fix divide-by-zero in rtsc_min(). The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic), Linux/Linux (generic), Siemens/SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (generic), Siemens/SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (generic) and additional mapped packages. Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 5.5. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps Linux/Linux (generic), Linux/Linux (generic), Siemens/SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (generic), Siemens/SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (generic) and additional mapped packages. Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| Linux/Linuxgeneric | >=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <ad8e8fec40290a8c8cf145c0deaadf76f80c5163 || >=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <ab1ff5890c7354afc7be56502fcfbd61f3b7ae4f || >=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <25b6821884713a31e2b49fb67b0ebd765b33e0a9 || >=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <c56f78614e7781aaceca9bd3cb2128bf7d45c3bd || >=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <b9e6431cbea8bb1fae8069ed099b4ee100499835 || >=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <17c1b9807b8a67d676b6dcf749ee932ebaa7f568 || >=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <d0aefec1b1a1ba2c1d251028dc2c4e5b4ce1fea5 || >=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <4576100b8cd03118267513cafacde164b498b322 | ad8e8fec40290a8c8cf145c0deaadf76f80c5163, ab1ff5890c7354afc7be56502fcfbd61f3b7ae4f, 25b6821884713a31e2b49fb67b0ebd765b33e0a9, c56f78614e7781aaceca9bd3cb2128bf7d45c3bd, b9e6431cbea8bb1fae8069ed099b4ee100499835, 17c1b9807b8a67d676b6dcf749ee932ebaa7f568, d0aefec1b1a1ba2c1d251028dc2c4e5b4ce1fea5, 4576100b8cd03118267513cafacde164b498b322 |
| Linux/Linuxgeneric | 2.6.12 | Not reported |
| Siemens/SIMATIC S7-1500 CPU 1518-4 PN/DP MFPgeneric | >=V3.1.6 <* | * |
| Siemens/SIMATIC S7-1500 CPU 1518-4 PN/DP MFPgeneric | >=V3.1.5 <* | * |
| Siemens/SIMATIC S7-1500 CPU 1518F-4 PN/DP MFPgeneric | >=V3.1.6 <* | * |
| Siemens/SIMATIC S7-1500 CPU 1518F-4 PN/DP MFPgeneric | >=V3.1.5 <* | * |
| Siemens/SIPLUS S7-1500 CPU 1518-4 PN/DP MFPgeneric | >=V3.1.6 <* | * |
| Siemens/SIPLUS S7-1500 CPU 1518-4 PN/DP MFPgeneric | >=V3.1.5 <* | * |
Published upstream
Apr 13, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Jul 14, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Jul 14, 2026
In the Linux kernel, the following vulnerability has been resolved: net/sched: sch_hfsc: fix divide-by-zero in rtsc_min() m2sm() converts a u32 slope to a u64 scaled value. For large inputs (e.g. m1=4000000000), the result can reach 2^32. rtsc_min() stores the difference of two such u64 values in a u32 variable `dsm` and uses it as a divisor. When the difference is exactly 2^32 the truncation yields zero, causing a divide-by-zero oops in the concave-curve intersection path: Oops: divide error: 0000 RIP: 0010:rtsc_min (net/sched/sch_hfsc.c:601) Call Trace: init_ed (net/sched/sch_hfsc.c:629) hfsc_enqueue (net/sched/sch_hfsc.c:1569) [...] Widen `dsm` to u64 and replace do_div() with div64_u64() so the full difference is preserved.
Quoted source text, attributed separately from HOL analysis.
CVSS is 5.5. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps Linux/Linux (generic), Linux/Linux (generic), Siemens/SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (generic), Siemens/SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (generic) and additional mapped packages. Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| Linux/Linuxgeneric | >=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <ad8e8fec40290a8c8cf145c0deaadf76f80c5163 || >=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <ab1ff5890c7354afc7be56502fcfbd61f3b7ae4f || >=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <25b6821884713a31e2b49fb67b0ebd765b33e0a9 || >=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <c56f78614e7781aaceca9bd3cb2128bf7d45c3bd || >=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <b9e6431cbea8bb1fae8069ed099b4ee100499835 || >=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <17c1b9807b8a67d676b6dcf749ee932ebaa7f568 || >=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <d0aefec1b1a1ba2c1d251028dc2c4e5b4ce1fea5 || >=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <4576100b8cd03118267513cafacde164b498b322 | ad8e8fec40290a8c8cf145c0deaadf76f80c5163, ab1ff5890c7354afc7be56502fcfbd61f3b7ae4f, 25b6821884713a31e2b49fb67b0ebd765b33e0a9, c56f78614e7781aaceca9bd3cb2128bf7d45c3bd, b9e6431cbea8bb1fae8069ed099b4ee100499835, 17c1b9807b8a67d676b6dcf749ee932ebaa7f568, d0aefec1b1a1ba2c1d251028dc2c4e5b4ce1fea5, 4576100b8cd03118267513cafacde164b498b322 |
| Linux/Linuxgeneric | 2.6.12 | Not reported |
| Siemens/SIMATIC S7-1500 CPU 1518-4 PN/DP MFPgeneric | >=V3.1.6 <* | * |
| Siemens/SIMATIC S7-1500 CPU 1518-4 PN/DP MFPgeneric | >=V3.1.5 <* | * |
| Siemens/SIMATIC S7-1500 CPU 1518F-4 PN/DP MFPgeneric | >=V3.1.6 <* | * |
| Siemens/SIMATIC S7-1500 CPU 1518F-4 PN/DP MFPgeneric | >=V3.1.5 <* | * |
| Siemens/SIPLUS S7-1500 CPU 1518-4 PN/DP MFPgeneric | >=V3.1.6 <* | * |
| Siemens/SIPLUS S7-1500 CPU 1518-4 PN/DP MFPgeneric | >=V3.1.5 <* | * |
Published upstream
Apr 13, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Jul 14, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Jul 14, 2026
In the Linux kernel, the following vulnerability has been resolved: net/sched: sch_hfsc: fix divide-by-zero in rtsc_min() m2sm() converts a u32 slope to a u64 scaled value. For large inputs (e.g. m1=4000000000), the result can reach 2^32. rtsc_min() stores the difference of two such u64 values in a u32 variable `dsm` and uses it as a divisor. When the difference is exactly 2^32 the truncation yields zero, causing a divide-by-zero oops in the concave-curve intersection path: Oops: divide error: 0000 RIP: 0010:rtsc_min (net/sched/sch_hfsc.c:601) Call Trace: init_ed (net/sched/sch_hfsc.c:629) hfsc_enqueue (net/sched/sch_hfsc.c:1569) [...] Widen `dsm` to u64 and replace do_div() with div64_u64() so the full difference is preserved.
Quoted source text, attributed separately from HOL analysis.