Incorrect TLB flushes via premature entry publication
Published Oct 18, 2026 · Updated Oct 18, 2026
Linux RISC-V KVM memory-ordering errors allow attackers to cause incorrect TLB flush ranges through nested HFENCE entries. The __kvm_riscv_nacl_hfence() function publishes Config.Pending before updating the page number and count, allowing the consumer to use stale parameters. Reachability requires RISC-V nested acceleration; the published record does not establish attacker privileges or a resulting crash, data disclosure, or privilege escalation.
Summary
What happened
Linux RISC-V KVM memory-ordering errors allow attackers to cause incorrect TLB flush ranges through nested HFENCE entries. The __kvm_riscv_nacl_hfence() function publishes Config.Pending before updating the page number and count, allowing the consumer to use stale parameters. Reachability requires RISC-V nested acceleration; the published record does not establish attacker privileges or a resulting crash, data disclosure, or privilege escalation.
The record
- CVE
- CVE-2026-98639
- Published
- Oct 18, 2026
- Updated
- Oct 18, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux
- Classifications
- Unavailable
- Attack vector
- Unavailable
- Privileges
- Unavailable
Timeline
How it unfolded
- Oct 18, 2026CVE publishedPublication date reported by the CVE source.
- Oct 18, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=6.13
- Affected versionversion=d466c19cead5904d4d5d92adb2b213b411d3b849 <6da466502621381fa88a6684290923d25c559266
- Affected versionversion=d466c19cead5904d4d5d92adb2b213b411d3b849 <b3d346838ec65fac7fd83f5dbcedd13cadfffddb
- Affected versionversion=d466c19cead5904d4d5d92adb2b213b411d3b849 <d6de766d8d26d71b714f548192099112def50a9c
What conditions does exploitation require?
What is affected?
Published CVSS scores
No CVSS assessment is available in this record.
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Activity data is delayed. The latest report is Sep 28, 2026.
Weakness, pattern, technique
No sourced classifications are available.
Public exploit references
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Technologies
Your stack
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Your stack
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