CVE-2026-63895

Kernel-memory disclosure via oversized FunctionFS copy

Published Jul 19, 2026 · Updated Jul 19, 2026

Information disclosure in Linux Kernel FunctionFS allows attackers controlling a privileged gadget daemon to read kernel slab residue. The ffs_ep0_read() path allocates the Setup-packet length with kmalloc() but copies that full length after __ffs_ep0_queue_wait() reports fewer received bytes. Reachability requires a privileged gadget daemon and a USB host build that bypasses normal short-wLength rejection; unprivileged userspace cannot reach the device node.

CVSS severityUnavailable
Unscored
EPSS probability0.26%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Information disclosure in Linux Kernel FunctionFS allows attackers controlling a privileged gadget daemon to read kernel slab residue. The ffs_ep0_read() path allocates the Setup-packet length with kmalloc() but copies that full length after __ffs_ep0_queue_wait() reports fewer received bytes. Reachability requires a privileged gadget daemon and a USB host build that bypasses normal short-wLength rejection; unprivileged userspace cannot reach the device node.

The record

CVE
CVE-2026-63895
Published
Jul 19, 2026
Updated
Jul 19, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
T1005
Attack vector
local
Privileges
admin

Timeline

How it unfolded

  1. Jul 19, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 19, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=2.6.35
  2. Affected versionversion=ddf8abd2599491cbad959c700b90ba72a5dce8d0 <23c1f7deb9dd8447ecde749850676302aa1e2bd3
  3. Affected versionversion=ddf8abd2599491cbad959c700b90ba72a5dce8d0 <4e036c10e7f4df5d951c69cc3697bc8e209c6d02
  4. Affected versionversion=ddf8abd2599491cbad959c700b90ba72a5dce8d0 <607730a414773a7cbe3037a64a6c64e72689ff5e
  5. Affected versionversion=ddf8abd2599491cbad959c700b90ba72a5dce8d0 <88874a19b2b093bfaaa1c0090fa536c44da8c08b
  6. Affected versionversion=ddf8abd2599491cbad959c700b90ba72a5dce8d0 <90ccf5fb63243fae1b4b3200f3310500500ecf2e
  7. Affected versionversion=ddf8abd2599491cbad959c700b90ba72a5dce8d0 <af32dbb2ca0b3d09271ab718d13857a457fa16f2
  8. Affected versionversion=ddf8abd2599491cbad959c700b90ba72a5dce8d0 <e835bf9a055f71874065a40780ca5560b7df8b33

What conditions does exploitation require?

Attack vectorlocal
Required privilegesadmin

What is affected?

The Linux Kernel Organization · Linux Kernelversion=2.6.35; version=ddf8abd2599491cbad959c700b90ba72a5dce8d0 <23c1f7deb9dd8447ecde749850676302aa1e2bd3; version=ddf8abd2599491cbad959c700b90ba72a5dce8d0 <4e036c10e7f4df5d951c69cc3697bc8e209c6d02; version=ddf8abd2599491cbad959c700b90ba72a5dce8d0 <607730a414773a7cbe3037a64a6c64e72689ff5e; version=ddf8abd2599491cbad959c700b90ba72a5dce8d0 <88874a19b2b093bfaaa1c0090fa536c44da8c08b; version=ddf8abd2599491cbad959c700b90ba72a5dce8d0 <90ccf5fb63243fae1b4b3200f3310500500ecf2e; version=ddf8abd2599491cbad959c700b90ba72a5dce8d0 <af32dbb2ca0b3d09271ab718d13857a457fa16f2; version=ddf8abd2599491cbad959c700b90ba72a5dce8d0 <e835bf9a055f71874065a40780ca5560b7df8b33

Published CVSS scores

No CVSS assessment is available in this record.

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesadmin
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1005Data from Local System

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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