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Vulnerabilities

Vulnerability · CVE-2026-99000

drm/xe: Fix shrinker accounting double-subtraction on nested external pins

Published Oct 23, 2026 · catalog updated Oct 23, 2026 · Linux Linux

Last checked Nov 6, 2026. A connected source was read within the last 7 days.

Check if you run it

No confirmed exploitation is on record for CVE-2026-99000. EPSS is 0.18%. Act only if a listed version of Linux Linux is installed.

Gaps on this record

  • No version range is stored. A customer cannot check an installed version against this record.
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.

Same product and reporting

Severity
Medium—
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.18%
Remediation
Not established
Affected products
vendor Linux Linux

In the Linux kernel, the following vulnerability has been resolved: drm/xe: Fix shrinker accounting double-subtraction on nested external pins xe_bo_pin_external() and xe_bo_unpin_external() support nested pins, since the underlying ttm_bo_pin()/ttm_bo_unpin() maintain a pin_count refcount rather than a boolean. However, the shrinker accounting calls xe_ttm_tt_account_subtract() and xe_ttm_tt_account_add() are invoked unconditionally on every pin_external()/unpin_external() call, instead of only on the transition into and out of the pinned state. An external BO (dma-buf) can be pinned more than once while already pinned, for example when it has multiple attachments/importers, each independently calling xe_bo_pin_external(). Each such nested pin subtracts the BO's pages from the shrinker's accounting again, even though the BO's pages were already removed from consideration by the first pin. Symmetrically, each nested unpin adds them back again before the BO is actually unpinned. This desynchronizes the shrinker's page and object counts from reality, and since they are declared as signed long but interpreted as unsigned long in xe_shrinker_count(), the underflow can turn into an enormous shrinkable/purgeable page count, causing the shrinker to be invoked excessively under memory pressure. Guard the accounting calls with the same pin-count transition checks already used to guard the pinned_link list maintenance, so accounting is only updated on the outermost pin and the final unpin. While centralizing this logic into xe_bo_account_pin()/ xe_bo_account_unpin(), also close a second, related accounting gap affecting imported dma-bufs. For an imported bo's ttm_tt, xe's ttm_tt_populate hook (xe_ttm_tt_populate()) early-returns without calling xe_ttm_tt_account_add(), since TTM_TT_FLAG_EXTERNAL is set without TTM_TT_FLAG_EXTERNAL_MAPPABLE. However, TTM core's ttm_tt_populate() wrapper unconditionally marks the tt as populated on driver-hook success, so ttm_tt_is_populated()

Are you affected?

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  • vendor Linux Linuxversion unspecified

How to fix CVE-2026-99000

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2026-99000. EPSS is 0.18%. Act only if a listed version of Linux Linux is installed.

Which versions are affected?

Affected version ranges are not on this record. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

No weakness class is stored. EPSS 0.18%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Oct 23, 2026 · Tenable CVE Database

    Detected

    In the Linux kernel, the following vulnerability has been resolved: drm/xe: Fix shrinker accounting double-subtraction on nested external pins xe_bo_pin_external() and xe_bo_unpin_external() support nested pins, since the underlying ttm_bo_pin()/ttm_bo_unpin() maintain a pin_count refcount rather than a boolean. However, the shrinker accounting calls xe_ttm_tt_account_subtract() and xe_ttm_tt_acco

  2. Oct 23, 2026 · CVE.org

    Updated

    In the Linux kernel, the following vulnerability has been resolved: drm/xe: Fix shrinker accounting double-subtraction on nested external pins xe_bo_pin_external() and xe_bo_unpin_external() support nested pins, since the underlying ttm_bo_pin()/ttm_bo_unpin() maintain a pin_count refcount rather than a boolean. However, the shrinker accounting calls xe_ttm_tt_account_subtract() and xe_ttm_tt_acco

Sources

  • CVE.orgVulnerability recordCVE-2026-99000

    In the Linux kernel, the following vulnerability has been resolved: drm/xe: Fix shrinker accounting double-subtraction on nested external pins xe_bo_pin_external() and xe_bo_unpin_external() support nested pins, since the underlying ttm_bo_pin()/ttm_bo_unpin() maintain a pin_coun

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-99000

    30-day exploitation probability 0.18%

    first.org
  • Tenable CVE DatabaseVulnerability recordCVE-2026-99000

    In the Linux kernel, the following vulnerability has been resolved: drm/xe: Fix shrinker accounting double-subtraction on nested external pins xe_bo_pin_external() and xe_bo_unpin_external() support nested pins, since the underlying ttm_bo_pin()/ttm_bo_unpin() maintain a pin_count refcount rather than a boolean. However, the shrinker accounting calls xe_ttm_tt_account_subtract() and xe_ttm_tt_acco

    tenable.com

References

Freshness

Last verified in this catalog Nov 6, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.

  • FIRST EPSSOct 28, 2026
  • CVE.orgOct 25, 2026
  • Tenable CVE DatabaseOct 23, 2026