Answer in brief
CVE-2026-98040 records a Unknown severity vulnerability in bpf: Mark the zero register precise for a register-form NULL check. The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
A CVSS score is not reported in the current record. 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). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| Linux/Linuxgeneric | >=2f4cb53eed448c1aeb6f4b40cf9c810716d8218c <ddca9a3b8833168dda3e62676648a636fb3f221c || >=2f4cb53eed448c1aeb6f4b40cf9c810716d8218c <6aed0134d3cda6382385a734ae0158eb7df6b142 | ddca9a3b8833168dda3e62676648a636fb3f221c, 6aed0134d3cda6382385a734ae0158eb7df6b142 |
| Linux/Linuxgeneric | 7.1 | Not reported |
Published upstream
Sep 25, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Sep 25, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Sep 25, 2026
In the Linux kernel, the following vulnerability has been resolved: bpf: Mark the zero register precise for a register-form NULL check check_cond_jmp_op() accepts "if rA <op> rB" as a NULL check for a nullable pointer rA when rB is a scalar known to be zero, lifts PTR_MAYBE_NULL from rA in the corresponding branch and does not mark rB precise. Consider the following program: r0 = bpf_get_prandom_u32(); r6 = 1; /* the r6 == 0 path is explored first */ if (r0 == 0) goto 1f; r6 = 0; 1: r0 = bpf_map_lookup_elem(map, &0); /* absent, NULL at runtime */ if (r0 == r6) goto 2f; /* taken as a NULL check for r0 */ *(u8 *)(r0 + 0); /* verifier: map value; runtime: zero */ 2: return 0; The r6 == 0 path is explored first and the dereference is accepted. The r6 == 1 path is pruned at the checkpoint recorded for (1), so the comparison is never verified with a non-zero r6. At runtime a failed lookup returns NULL, NULL != 1 takes the non-NULL edge and the program dereferences a pointer that is zero.
Quoted source text, attributed separately from HOL analysis.