VulnerabilityPublished 23 Oct 2026

CVE-2026-98900: Linux kernel · xen/gntalloc: validate grant count before allocation

Source GCVE Database

Authoritative record:CVE-2026-98900

Not known to be exploited · fixed in e2806390aa1c4d5b3f7a68f10a56ae12c71c00d8 : update Linux kernel when convenient.

Data as of 26 Oct 2026, 12:30 UTC

Severity

Medium

Rated by Threat Radar · CVSS not yet scored by NVD

EPSS: 0.1% chance of exploitation in 30 days – higher than 7% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in e2806390aa1c4d5b3f7a68f10a56ae12c71c00d8, 2299822f3f466b5dcad2377bf63986199f881a6b, 720554c04acba80018ded069d3e0984bebaee891 +4

Exploitation evidence

Disclosed: evidence found.
CVE published 23 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-mwrq-hx54-3h97

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected ≥ dd3140588d9551235ebc2a0dacdca098e7677573, < e2806390aa1c4d5b3f7a68f10a56ae12c71c00d8	Fixed in e2806390aa1c4d5b3f7a68f10a56ae12c71c00d8
LinuxLinux	Affected ≥ dd3140588d9551235ebc2a0dacdca098e7677573, < 2299822f3f466b5dcad2377bf63986199f881a6b	Fixed in 2299822f3f466b5dcad2377bf63986199f881a6b
LinuxLinux	Affected ≥ dd3140588d9551235ebc2a0dacdca098e7677573, < 720554c04acba80018ded069d3e0984bebaee891	Fixed in 720554c04acba80018ded069d3e0984bebaee891
LinuxLinux	Affected ≥ dd3140588d9551235ebc2a0dacdca098e7677573, < 231542f4e43cf9837cb520664545e85fbe666b7b	Fixed in 231542f4e43cf9837cb520664545e85fbe666b7b
LinuxLinux	Affected ≥ dd3140588d9551235ebc2a0dacdca098e7677573, < 641de086a05f349de7fc548612432bc2fed721ca	Fixed in 641de086a05f349de7fc548612432bc2fed721ca
LinuxLinux	Affected ≥ dd3140588d9551235ebc2a0dacdca098e7677573, < 84d5727cef8eb9c8a28210ad248f1c70b223b065	Fixed in 84d5727cef8eb9c8a28210ad248f1c70b223b065

AI-suggested

A fix has been implemented in the Linux kernel to validate the grant count before allocation, preventing counts above the global limit from proceeding. Users should apply the official kernel update that includes this patch once available.

Description

A vulnerability in the Linux kernel's xen/gntalloc component was resolved by validating the grant count before allocation. The function gntalloc_ioctl_alloc() previously allocated memory for the grant-id array before verifying if the requested count was within the global grant limit, potentially leading to improper memory allocation. The fix involves rejecting counts above the limit before allocation and using a subtraction-based check under a mutex to prevent integer wraparound during count addition. Additionally, 64-bit arithmetic is used for page-size multiplication to ensure correctness.

References

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