Answer in brief
CVE-2026-98639 records a Unknown severity vulnerability in KVM: riscv: Fix NACL hfence entry update order. 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 | >=d466c19cead5904d4d5d92adb2b213b411d3b849 <d6de766d8d26d71b714f548192099112def50a9c || >=d466c19cead5904d4d5d92adb2b213b411d3b849 <6da466502621381fa88a6684290923d25c559266 || >=d466c19cead5904d4d5d92adb2b213b411d3b849 <b3d346838ec65fac7fd83f5dbcedd13cadfffddb | d6de766d8d26d71b714f548192099112def50a9c, 6da466502621381fa88a6684290923d25c559266, b3d346838ec65fac7fd83f5dbcedd13cadfffddb |
| Linux/Linuxgeneric | 6.13 | Not reported |
Published upstream
Oct 18, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Oct 19, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Oct 18, 2026
In the Linux kernel, the following vulnerability has been resolved: KVM: riscv: Fix NACL hfence entry update order The SBI v3.0 specification (section 15.1.2) requires a nested HFENCE entry to be populated as follows: 1) find an unused entry with Config.Pending == 0 2) update the Page_Number and Page_Count words 3) update the Config word with Config.Pending set __kvm_riscv_nacl_hfence() writes the Config word first, so the SBI implementation (or NACL hardware) can observe a pending entry with pnum/pcount values left over from the previous use of that entry, resulting in incorrect TLB flush ranges. Write pnum and pcount first and the Config word last. Since the consumer is an external agent on coherent shared memory, use WRITE_ONCE() to stop the compiler from reordering the stores and smp_wmb() to make the parameter words globally visible before the Pending bit is set.
Quoted source text, attributed separately from HOL analysis.