VulnerabilityPublished 24 Sep 2026Updated 19 Oct 2026

CVE-2026-93233: Linux kernel · drm/nouveau/dmem: fix callocated underflow on large folio split

Affects Linux kernelSource CVE Database V5

Not known to be exploited : upgrade to c2256c044a1df39c8aad4dd2d6f709b2533e2d7a or 0163b92946d0a7c816f619c57a4d9867954dd106 when convenient.

Data as of 26 Oct 2026, 12:55 UTC

Severity

Unrated

Rated by Threat Radar · CVSS not yet scored by NVD

EPSS: 0.1% chance of exploitation in 30 days – higher than 4% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in c2256c044a1df39c8aad4dd2d6f709b2533e2d7a, 0163b92946d0a7c816f619c57a4d9867954dd106

Exploitation evidence

Disclosed: evidence found.
CVE published 24 Sep 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 c2256c044a1df39c8aad4dd2d6f709b2533e2d7a or 0163b92946d0a7c816f619c57a4d9867954dd106.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected ≥ c3228747107705d47c7e9a03598a434a0380cb73, < c2256c044a1df39c8aad4dd2d6f709b2533e2d7a	Fixed in c2256c044a1df39c8aad4dd2d6f709b2533e2d7a
LinuxLinux	Affected ≥ c3228747107705d47c7e9a03598a434a0380cb73, < 0163b92946d0a7c816f619c57a4d9867954dd106	Fixed in 0163b92946d0a7c816f619c57a4d9867954dd106
LinuxLinux	Affected =6.19	Fixed in–

Description

In the Linux kernel, the following vulnerability has been resolved: drm/nouveau/dmem: fix callocated underflow on large folio split nouveau_dmem_folio_free() drops chunk->callocated once per freed folio, while a large (compound) device-private folio is only counted once when it is allocated. When such a folio is split, the mm core invokes ->folio_split() (nouveau_dmem_folio_split()) once for each new sub-folio, but the hook only fixes up the sub-folio metadata and leaves chunk->callocated unchanged. Each resulting sub-folio is later freed separately, so after a split the single allocation (+1) is met by N frees (-N), leaving chunk->callocated short by N-1. On the first split/free cycle it underflows: WARN_ON(!chunk->callocated) fires, the unsigned counter wraps and never returns to zero, so the chunk can no longer be reclaimed (nouveau_dmem_fini() also warns on the leaked count). Account for the new sub-folio in the split hook, under the same lock as nouveau_dmem_folio_free(), so the count stays balanced.

References

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