VulnerabilityPublished 18 Oct 2026

CVE-2026-98638: Linux kernel · KVM: arm64: Validate the SVE vector length in pkvm_vcpu_init_sve()

Source GCVE Database

Authoritative record:CVE-2026-98638· Medium

Not known to be exploited · fixed in faf66e55e87498ab4bf88cdf9a629e61b3f2d3bc : update Linux kernel when convenient.

Data as of 26 Oct 2026, 14:05 UTC

Severity

Medium

Rated by Threat Radar · CVSS not yet scored by NVD

EPSS: 0.1% chance of exploitation in 30 days – higher than 5% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in faf66e55e87498ab4bf88cdf9a629e61b3f2d3bc, bae3e4493046de4fefa15f809d9b8dc114e84a3d, 2a2eb10795a1e495aebc7f829ccecb72c05b4fd9

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.

ghsa-jqwq-p3w6-jffx

What to do

Upgrade Linux kernel to faf66e55e87498ab4bf88cdf9a629e61b3f2d3bc, bae3e4493046de4fefa15f809d9b8dc114e84a3d or 2a2eb10795a1e495aebc7f829ccecb72c05b4fd9.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected ≥ 5db1bef933427aa467ad89c7b695a84a6b4afe16, < faf66e55e87498ab4bf88cdf9a629e61b3f2d3bc	Fixed in faf66e55e87498ab4bf88cdf9a629e61b3f2d3bc
LinuxLinux	Affected ≥ 5db1bef933427aa467ad89c7b695a84a6b4afe16, < bae3e4493046de4fefa15f809d9b8dc114e84a3d	Fixed in bae3e4493046de4fefa15f809d9b8dc114e84a3d
LinuxLinux	Affected ≥ 5db1bef933427aa467ad89c7b695a84a6b4afe16, < 2a2eb10795a1e495aebc7f829ccecb72c05b4fd9	Fixed in 2a2eb10795a1e495aebc7f829ccecb72c05b4fd9
LinuxLinux	Affected =6.16	Fixed in–

AI-suggested

A fix has been implemented in the Linux kernel to validate the SVE vector length properly in pkvm_vcpu_init_sve(). Users should apply the official kernel updates that include this patch. Since no vendor advisory or patch links are provided, check the Linux kernel mailing lists or official repositories for the patch and update guidance.

Description

A vulnerability in the Linux kernel's KVM arm64 implementation was resolved by improving validation of the SVE vector length in the pkvm_vcpu_init_sve() function. The issue involved insufficient validation of the host-provided sve_max_vl value, which could lead to a fatal condition at EL2 due to an invalid vector length causing a WARN_ON() trigger. The fix ensures that sve_vl_valid() is checked before calculating the state size, preventing invalid lengths from causing kernel faults.

References

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