CyberSecBulletin
CVE-2025-39757NVD status: Modified

Linux: Out-of-bounds Read

Published Updated By the CyberSecBulletin desk

CVE-2025-39757 is a high-severity out-of-bounds read vulnerability in Linux, with a CVSS 3.1 base score of 7.1 out of 10. It can be exploited with local access to the system by an attacker with a low-privileged account, without any action from a user. The record lists versions 799c06ad4c9c790c265e8b6b94947213f1fb389c, 786571b10b1ae6d90e1242848ce78ee7e1d493c4, 275e37532e8ebe25e8a4069b2d9f955bfd202a46 as the first without the flaw, so updating Linux to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.19% chance of exploitation within 30 days, which is low compared with other CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Update Linux to 799c06ad4c9c790c265e8b6b94947213f1fb389c or 786571b10b1ae6d90e1242848ce78ee7e1d493c4 or 275e37532e8ebe25e8a4069b2d9f955bfd202a46 or 47ab3d820cb0a502bd0074f83bb3cf7ab5d79902, whichever matches your release line, or a later version.
  2. Update SIMATIC CN 4100 to V5.0 or a later version.
  3. Update Linux Kernel to 5.4.297 or 5.10.241 or 5.15.190 or 6.1.149, whichever matches your release line, or a later version.

Affected products and versions

VendorProductAffected versionsFixed in
LinuxLinux11785ef53228d23ec386f5fe4a34601536f0c891 up to, but not including, 799c06ad4c9c790c265e8b6b94947213f1fb389c; 11785ef53228d23ec386f5fe4a34601536f0c891 up to, but not including, 786571b10b1ae6d90e1242848ce78ee7e1d493c4; 11785ef53228d23ec386f5fe4a34601536f0c891 up to, but not including, 275e37532e8ebe25e8a4069b2d9f955bfd202a46; 11785ef53228d23ec386f5fe4a34601536f0c891 up to, but not including, 47ab3d820cb0a502bd0074f83bb3cf7ab5d79902; 11785ef53228d23ec386f5fe4a34601536f0c891 up to, but not including, 1034719fdefd26caeec0a44a868bb5a412c2c1a5; 11785ef53228d23ec386f5fe4a34601536f0c891 up to, but not including, ae17b3b5e753efc239421d186cd1ff06e5ac296e; 11785ef53228d23ec386f5fe4a34601536f0c891 up to, but not including, dfdcbcde5c20df878178245d4449feada7d5b201; 11785ef53228d23ec386f5fe4a34601536f0c891 up to, but not including, 7ef3fd250f84494fb2f7871f357808edaa1fc6ce; and 2 more ranges799c06ad4c9c790c265e8b6b94947213f1fb389c, 786571b10b1ae6d90e1242848ce78ee7e1d493c4, 275e37532e8ebe25e8a4069b2d9f955bfd202a46, 47ab3d820cb0a502bd0074f83bb3cf7ab5d79902, 1034719fdefd26caeec0a44a868bb5a412c2c1a5, ae17b3b5e753efc239421d186cd1ff06e5ac296e
SiemensSIMATIC CN 4100before V5.0V5.0
LinuxLinux Kernel4.19 up to, but not including, 5.4.297; 5.5 up to, but not including, 5.10.241; 5.11 up to, but not including, 5.15.190; 5.16 up to, but not including, 6.1.149; 6.2 up to, but not including, 6.6.103; 6.7 up to, but not including, 6.12.43; 6.13 up to, but not including, 6.15.11; 6.16 up to, but not including, 6.16.2; and 1 more ranges5.4.297, 5.10.241, 5.15.190, 6.1.149, 6.6.103, 6.12.43
DebianDebian Linux11.0Not stated

Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
LocalThe attacker needs local access or must trick a user into running something.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Privileges required
LowA basic user account is enough.
User interaction
NoneNo action by a victim is required.
Scope
UnchangedImpact stays within the vulnerable component.
Confidentiality
HighAll data handled by the component can be read.
Integrity
NoneNothing can be modified.
Availability
HighThe component can be taken down completely.

Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H. Scored by NVD.

Official description

In the Linux kernel, the following vulnerability has been resolved: ALSA: usb-audio: Validate UAC3 cluster segment descriptors UAC3 class segment descriptors need to be verified whether their sizes match with the declared lengths and whether they fit with the allocated buffer sizes, too. Otherwise malicious firmware may lead to the unexpected OOB accesses.

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Out-of-bounds Read

The product reads data past the end, or before the beginning, of the intended buffer.

How developers prevent this class of flaw

  • Use a language that provides appropriate memory abstractions.

More Out-of-bounds Read vulnerabilities (CWE-125)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: partial).
  3. Record last changed materially (score, affected products, status or references).

References

Third-party and government advisories

Recent Out-of-bounds Read vulnerabilities

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