VulnerabilityPublished 23 Oct 2026

CVE-2026-99000: Linux kernel · drm/xe: Fix shrinker accounting double-subtraction on nested external pins

Source GCVE Database

Authoritative record:CVE-2026-99000· Medium

Not known to be exploited · fixed in ab39bc55cf08208b8511b1c09926b1b646a8befc : 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 7% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in ab39bc55cf08208b8511b1c09926b1b646a8befc, 993c952e6832ad0aa4be82e11f0760b1f532090a, 83d5acca1f4f6132038ea88c72c5844f62e42d44

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-m59j-mhqw-68mx

What to do

Upgrade Linux kernel to ab39bc55cf08208b8511b1c09926b1b646a8befc, 993c952e6832ad0aa4be82e11f0760b1f532090a or 83d5acca1f4f6132038ea88c72c5844f62e42d44.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected ≥ 00c8efc3180f0cf919b53980e969430657e01685, < ab39bc55cf08208b8511b1c09926b1b646a8befc	Fixed in ab39bc55cf08208b8511b1c09926b1b646a8befc
LinuxLinux	Affected ≥ 00c8efc3180f0cf919b53980e969430657e01685, < 993c952e6832ad0aa4be82e11f0760b1f532090a	Fixed in 993c952e6832ad0aa4be82e11f0760b1f532090a
LinuxLinux	Affected ≥ 00c8efc3180f0cf919b53980e969430657e01685, < 83d5acca1f4f6132038ea88c72c5844f62e42d44	Fixed in 83d5acca1f4f6132038ea88c72c5844f62e42d44
LinuxLinux	Affected =6.15	Fixed in–

AI-suggested

A fix has been implemented in the Linux kernel drm/xe subsystem to correctly handle shrinker accounting by updating counts only on pin-count transitions and excluding imported dma-bufs from accounting. Users should update to a kernel version that includes this fix once available. Patch status is not explicitly confirmed in the provided data; check the vendor advisory or Linux kernel mailing lists for the official fixed version and apply the update accordingly.

Description

A vulnerability in the Linux kernel's drm/xe component caused incorrect shrinker accounting due to double-subtraction of pages when nested external pins occur on buffer objects. This desynchronization can lead to excessive invocation of the shrinker under memory pressure. The issue was fixed by ensuring accounting updates only occur on the outermost pin and final unpin, and by excluding imported dma-bufs from shrinker accounting to prevent underflows.

Impact

The vulnerability causes the shrinker's page and object counts to become inaccurate, potentially underflowing and leading to excessive shrinker invocation under memory pressure. This can degrade system performance due to unnecessary memory reclaim activity. There is no indication of direct memory corruption or privilege escalation. No known exploits in the wild have been reported.

Summary

The Linux kernel's drm/xe subsystem mishandled shrinker accounting for nested external pins on buffer objects (BOs). Functions xe_bo_pin_external() and xe_bo_unpin_external() support nested pins, but the accounting calls xe_ttm_tt_account_subtract() and xe_ttm_tt_account_add() were invoked unconditionally on every pin/unpin, rather than only on transitions into and out of the pinned state. This caused the shrinker's page and object counts to become desynchronized, potentially underflowing and resulting in an erroneously large shrinkable page count. Additionally, imported dma-bufs were improperly accounted for, causing further underflows. The fix involved guarding accounting calls with pin-count transition checks and excluding imported dma-bufs from accounting, centralizing logic in xe_bo_account_pin() and xe_bo_account_unpin().

References

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