CVE-2026-74635

Local kernel memory disclosure via unchecked glyph index

Published Aug 22, 2026 · Updated Aug 25, 2026

Out-of-bounds read in Linux fbdev bitblit allows local users to disclose kernel memory or crash the system via an invalid console glyph index. The bit_cursor() path uses a screen-buffer value masked for up to 512 glyphs to index vc_font.data without clamping it to the current font's charcount. Access to /dev/vcsa or control of an owned virtual console is required; triggering cursor rendering can expose kernel memory or stop the system.

CVSS severity7.8
High
EPSS probability0.13%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Out-of-bounds read in Linux fbdev bitblit allows local users to disclose kernel memory or crash the system via an invalid console glyph index. The bit_cursor() path uses a screen-buffer value masked for up to 512 glyphs to index vc_font.data without clamping it to the current font's charcount. Access to /dev/vcsa or control of an owned virtual console is required; triggering cursor rendering can expose kernel memory or stop the system.

The record

CVE
CVE-2026-74635
Published
Aug 22, 2026
Updated
Aug 25, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-125, T1499.004
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Aug 22, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 25, 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=0998a6cb232674408a03e8561dc15aa266b2f53b <250159ace2dc53c1bdad267aa8da51b638748700
  2. Affected versionversion=18c4ef4e765a798b47980555ed665d78b71aeadf <9ea879862e66e354e616028c31b39aa3eb6d35d8
  3. Affected versionversion=18c4ef4e765a798b47980555ed665d78b71aeadf <bc9db0d879c655d5dfd8add32fd60f13e65d132c
  4. Affected versionversion=18c4ef4e765a798b47980555ed665d78b71aeadf <e033cbf3975a8465f879ebd5989dc35b04423a4d
  5. Affected versionversion=5.10.247 <5.10.265
  6. Affected versionversion=5.15.197 <5.15.216
  7. Affected versionversion=5.4.302 <5.5
  8. Affected versionversion=6.1.159 <6.1.183
  9. Affected versionversion=6.12.58 <6.12.104
  10. Affected versionversion=6.17.8 <6.18
  11. Affected versionversion=6.18
  12. Affected versionversion=6.6.117 <6.6.152
  13. Affected versionversion=901f44227072be60812fe8083e83e1533c04eed1 <c1e7351767dd30fc574395c82121e4c67b882da3
  14. Affected versionversion=9ba1a7802ca9a2590cef95b253e6526f4364477f <94134d70abf9273b70499d97d0adc9185ef21091
  15. Affected versionversion=a10cede006f9614b465cf25609a8753efbfd45cc
  16. Affected versionversion=c12003bf91fdff381c55ef54fef3e961a5af2545 <bf750cfeacf4e47ac72dadc7f05839696efb8576
  17. Affected versionversion=db5c9a162d2f42bcc842b76b3d935dcc050a0eec <46336f476484f36145e5117e72d7b590f47433ee
  18. Affected versionversion=efaf89a75a29b2d179bf4fe63ca62852e93ad620

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=0998a6cb232674408a03e8561dc15aa266b2f53b <250159ace2dc53c1bdad267aa8da51b638748700; version=18c4ef4e765a798b47980555ed665d78b71aeadf <9ea879862e66e354e616028c31b39aa3eb6d35d8; version=18c4ef4e765a798b47980555ed665d78b71aeadf <bc9db0d879c655d5dfd8add32fd60f13e65d132c; version=18c4ef4e765a798b47980555ed665d78b71aeadf <e033cbf3975a8465f879ebd5989dc35b04423a4d; version=5.10.247 <5.10.265; version=5.15.197 <5.15.216; version=5.4.302 <5.5; version=6.1.159 <6.1.183; version=6.12.58 <6.12.104; version=6.17.8 <6.18; version=6.18; version=6.6.117 <6.6.152; version=901f44227072be60812fe8083e83e1533c04eed1 <c1e7351767dd30fc574395c82121e4c67b882da3; version=9ba1a7802ca9a2590cef95b253e6526f4364477f <94134d70abf9273b70499d97d0adc9185ef21091; version=a10cede006f9614b465cf25609a8753efbfd45cc; version=c12003bf91fdff381c55ef54fef3e961a5af2545 <bf750cfeacf4e47ac72dadc7f05839696efb8576; version=db5c9a162d2f42bcc842b76b3d935dcc050a0eec <46336f476484f36145e5117e72d7b590f47433ee; version=efaf89a75a29b2d179bf4fe63ca62852e93ad620

Published CVSS scores

7.8Linux kernel CVE teamCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-125Out-of-bounds Read
T1499.004Application or System Exploitation

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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