CVE-2026-74640

Kernel memory corruption via oversized FCP meter map

Published Aug 22, 2026 · Updated Aug 25, 2026

Out-of-bounds write in Linux ALSA FCP allows local users to corrupt kernel memory through an oversized Level Meter map. fcp_ioctl_set_meter_map accepts as many as 255 channels, but fcp_meter_ctl_get writes one word per channel into a 128-entry snd_ctl_elem_value array without a sink-side bound. Installing the oversized map requires CAP_SYS_RAWIO; afterward, any process able to read controls on /dev/snd/controlC0 triggers the controlled overwrite.

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 write in Linux ALSA FCP allows local users to corrupt kernel memory through an oversized Level Meter map. fcp_ioctl_set_meter_map accepts as many as 255 channels, but fcp_meter_ctl_get writes one word per channel into a 128-entry snd_ctl_elem_value array without a sink-side bound. Installing the oversized map requires CAP_SYS_RAWIO; afterward, any process able to read controls on /dev/snd/controlC0 triggers the controlled overwrite.

The record

CVE
CVE-2026-74640
Published
Aug 22, 2026
Updated
Aug 25, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-787, T1068
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=46757a3e7d50dac923888e7fbe68377736f13c70 <620f1e52a46f604635efd0fb78138afd6a513b5d
  2. Affected versionversion=46757a3e7d50dac923888e7fbe68377736f13c70 <bb30e35c36ed00f24fa39aded811f64230a913b0
  3. Affected versionversion=46757a3e7d50dac923888e7fbe68377736f13c70 <bb61dc2ae59026f76db26e1909746908bc5b6f31
  4. Affected versionversion=6.14

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=46757a3e7d50dac923888e7fbe68377736f13c70 <620f1e52a46f604635efd0fb78138afd6a513b5d; version=46757a3e7d50dac923888e7fbe68377736f13c70 <bb30e35c36ed00f24fa39aded811f64230a913b0; version=46757a3e7d50dac923888e7fbe68377736f13c70 <bb61dc2ae59026f76db26e1909746908bc5b6f31; version=6.14

Published CVSS scores

7.0Red HatCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
7.8CVE.orgCVSS: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 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-787Out-of-bounds Write
T1068Exploitation for Privilege Escalation

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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