VulnerabilityPublished 18 Oct 2026

CVE-2026-98715: Linux kernel · KVM: SVM: Preserve TLB control (i.e. pending TLB flush) on failed VMRUN

Affects Linux kernelSource CVE Database V5

Not known to be exploited : upgrade to fd873c3d1b5240e80365f09e758e8c96b88a7cdb or 60d93c27859fb3ec5b5a689e24de303f166477d0 when convenient.

Data as of 26 Oct 2026, 17:16 UTC

Severity

Medium

Rated Medium by Threat Radar's AI analysis · CVSS not yet scored by NVD

EPSS: 0.1% chance of exploitation in 30 days – higher than 8% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in fd873c3d1b5240e80365f09e758e8c96b88a7cdb, 60d93c27859fb3ec5b5a689e24de303f166477d0

Exploitation evidence

Disclosed: evidence found.
CVE published 18 Oct 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade Linux kernel to fd873c3d1b5240e80365f09e758e8c96b88a7cdb or 60d93c27859fb3ec5b5a689e24de303f166477d0.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected ≥ 38e5e92fe8c02a8766459d505423b855caf9af1f, < fd873c3d1b5240e80365f09e758e8c96b88a7cdb	Fixed in fd873c3d1b5240e80365f09e758e8c96b88a7cdb
LinuxLinux	Affected ≥ 38e5e92fe8c02a8766459d505423b855caf9af1f, < 60d93c27859fb3ec5b5a689e24de303f166477d0	Fixed in 60d93c27859fb3ec5b5a689e24de303f166477d0
LinuxLinux	Affected =2.6.38	Fixed in–
Debiandebian/linux`pkg:deb/debian/linux`Other threats	Affected =2.6.38	Fixed in–

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

The vulnerability has been fixed in the Linux kernel in the commits referenced by hashes fd873c3d1b5240e80365f09e758e8c96b88a7cdb and 60d93c27859fb3ec5b5a689e24de303f166477d0. Users and administrators should update to these fixed versions or later to remediate the issue. No additional mitigation steps are indicated by the vendor advisory.

Description

CVE-2026-98715 addresses a flaw in the Linux kernel's KVM SVM implementation where the TLB control state was improperly reset on a failed VMRUN operation. This could cause the CPU to skip a required TLB flush, potentially leading to stale translations being used. The fix preserves the TLB control state on failure and tracks flush requirements per CPU to prevent this issue.

Impact

If exploited, this flaw could cause the CPU to skip necessary TLB flushes after a failed VMRUN, potentially leading to stale or incorrect memory translations being used by virtual machines. This could affect the isolation and correctness of virtualized environments. However, the impact is mitigated by the fact that guests can already trigger ASID flushes at similar rates, and the fix addresses the issue by preserving TLB control state and improving flush tracking.

Summary

The vulnerability in the Linux kernel's KVM SVM code involves resetting the VMCB's TLB control to 'do nothing' when a VMRUN instruction fails. Since the CPU only performs the requested TLB flush if VMRUN succeeds, clearing the TLB control on failure results in dropped TLB flushes. The patch explicitly preserves the TLB control state on failed VMRUNs and tracks the need to flush all ASIDs on a per-CPU basis, addressing the flaw. Although this may cause occasional unnecessary flushes on subsequent successful runs, this is considered acceptable given existing guest-triggerable flush conditions. The flaw is fixed in specific commits identified by their hashes.

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 26 Oct 2026, 09:59 UTC

Technical details

References

Community reviews

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