Linux: Out-of-bounds Read
CVE-2025-21687 is a high-severity out-of-bounds read vulnerability in Linux, with a CVSS 3.1 base score of 7.8 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 f21636f24b6786c8b13f1af4319fa75ffcf17f38, 9377cdc118cf327248f1a9dde7b87de067681dc9, d19a8650fd3d7aed8d1af1d9a77f979a8430eba1 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 0.24% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update Linux to f21636f24b6786c8b13f1af4319fa75ffcf17f38 or 9377cdc118cf327248f1a9dde7b87de067681dc9 or d19a8650fd3d7aed8d1af1d9a77f979a8430eba1 or ed81d82bb6e9df3a137f2c343ed689e6c68268ef, whichever matches your release line, or a later version.
- Update Linux Kernel to 5.4.290 or 5.10.234 or 5.15.178 or 6.1.128, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | 6e3f264560099869f68830cb14b3b3e71e5ac76a up to, but not including, f21636f24b6786c8b13f1af4319fa75ffcf17f38; 6e3f264560099869f68830cb14b3b3e71e5ac76a up to, but not including, 9377cdc118cf327248f1a9dde7b87de067681dc9; 6e3f264560099869f68830cb14b3b3e71e5ac76a up to, but not including, d19a8650fd3d7aed8d1af1d9a77f979a8430eba1; 6e3f264560099869f68830cb14b3b3e71e5ac76a up to, but not including, ed81d82bb6e9df3a137f2c343ed689e6c68268ef; 6e3f264560099869f68830cb14b3b3e71e5ac76a up to, but not including, 92340e6c5122d823ad064984ef7513eba9204048; 6e3f264560099869f68830cb14b3b3e71e5ac76a up to, but not including, f65ce06387f8c1fb54bd59e18a8428248ec68eaf; 6e3f264560099869f68830cb14b3b3e71e5ac76a up to, but not including, 6bcb8a5b70b80143db9bf12dfa7d53636f824d53; 6e3f264560099869f68830cb14b3b3e71e5ac76a up to, but not including, 1485932496a1b025235af8aa1e21988d6b7ccd54; and 5 more ranges | f21636f24b6786c8b13f1af4319fa75ffcf17f38, 9377cdc118cf327248f1a9dde7b87de067681dc9, d19a8650fd3d7aed8d1af1d9a77f979a8430eba1, ed81d82bb6e9df3a137f2c343ed689e6c68268ef, 92340e6c5122d823ad064984ef7513eba9204048, f65ce06387f8c1fb54bd59e18a8428248ec68eaf |
| Linux | Linux Kernel | 4.1 up to, but not including, 5.4.290; 5.5 up to, but not including, 5.10.234; 5.11 up to, but not including, 5.15.178; 5.16 up to, but not including, 6.1.128; 6.2 up to, but not including, 6.6.75; 6.7 up to, but not including, 6.12.12; 6.13 | 5.4.290, 5.10.234, 5.15.178, 6.1.128, 6.6.75, 6.12.12 |
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
- HighData or code can be modified at will.
- 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:H/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 7.8 | High | CNA |
| CVSS 3.1 | 7.8 | High | NVD |
Official description
In the Linux kernel, the following vulnerability has been resolved: vfio/platform: check the bounds of read/write syscalls count and offset are passed from user space and not checked, only offset is capped to 40 bits, which can be used to read/write out of bounds of the device.
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.
Timeline
- CVE record published.
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
- git.kernel.org/stable/c/1485932496a1b025235af8aa1e21988d6b7ccd54
- git.kernel.org/stable/c/665cfd1083866f87301bbd232cb8ba48dcf4acce
- git.kernel.org/stable/c/6bcb8a5b70b80143db9bf12dfa7d53636f824d53
- git.kernel.org/stable/c/92340e6c5122d823ad064984ef7513eba9204048
- git.kernel.org/stable/c/a20fcaa230f7472456d12cf761ed13938e320ac3
- git.kernel.org/stable/c/c981c32c38af80737a2fedc16e270546d139ccdd
- git.kernel.org/stable/c/ce9ff21ea89d191e477a02ad7eabf4f996b80a69
- git.kernel.org/stable/c/d19a8650fd3d7aed8d1af1d9a77f979a8430eba1
- git.kernel.org/stable/c/f21636f24b6786c8b13f1af4319fa75ffcf17f38
Other references
- git.kernel.org/stable/c/9377cdc118cf327248f1a9dde7b87de067681dc9
- git.kernel.org/stable/c/ed81d82bb6e9df3a137f2c343ed689e6c68268ef
- git.kernel.org/stable/c/f65ce06387f8c1fb54bd59e18a8428248ec68eaf
- lists.debian.org/debian-lts-announce/2025/03/msg00001.html
- lists.debian.org/debian-lts-announce/2025/03/msg00002.html
Recent Out-of-bounds Read vulnerabilities
- 7.5 High severity
- 9.1 Critical severity
- 7.5 High severity
- 7.5 High severity
- 7.5 High severity
- 7.1 High severity
Spotted an error? Tell us.