CyberSecBulletin
CVE-2025-21650NVD status: Modified

Linux: Out-of-bounds Write

Published Updated By the CyberSecBulletin desk

CVE-2025-21650 is a high-severity out-of-bounds write 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 a85246635466752b9af72188e4a839541120d952, 0575baa733fc4219f230aef22d5bc35d922f1e9a, 7997ddd46c54408bcba5e37fe18b4d832e45d4d4 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 0.25% 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 a85246635466752b9af72188e4a839541120d952 or 0575baa733fc4219f230aef22d5bc35d922f1e9a or 7997ddd46c54408bcba5e37fe18b4d832e45d4d4 or 6.5, whichever matches your release line, or a later version.
  2. Update Linux Kernel to 6.5 or 6.12.10, whichever matches your release line, or a later version.

Affected products and versions

VendorProductAffected versionsFixed in
LinuxLinux939ccd107ffcade20c9c7055a2e7ae0fd724fb72 up to, but not including, a85246635466752b9af72188e4a839541120d952; 939ccd107ffcade20c9c7055a2e7ae0fd724fb72 up to, but not including, 0575baa733fc4219f230aef22d5bc35d922f1e9a; 939ccd107ffcade20c9c7055a2e7ae0fd724fb72 up to, but not including, 7997ddd46c54408bcba5e37fe18b4d832e45d4d4; df34972a33d268a7113c119fe4e4b07a6819aa0c; 2b1fff96a297034f03466cfecda9824adafe16ed; 6.4.16 up to, but not including, 6.5; 6.5.3 up to, but not including, 6.6; 6.6a85246635466752b9af72188e4a839541120d952, 0575baa733fc4219f230aef22d5bc35d922f1e9a, 7997ddd46c54408bcba5e37fe18b4d832e45d4d4, 6.5, 6.6
LinuxLinux Kernel6.4.16 up to, but not including, 6.5; 6.5.3 up to, but not including, 6.12.10; 6.136.5, 6.12.10

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 systemScoreSeverityScored by
CVSS 3.17.1HighCNA
CVSS 3.17.8HighNVD
CVSS 3.17.8HighCISA (ADP)

Official description

In the Linux kernel, the following vulnerability has been resolved: net: hns3: fixed hclge_fetch_pf_reg accesses bar space out of bounds issue The TQP BAR space is divided into two segments. TQPs 0-1023 and TQPs 1024-1279 are in different BAR space addresses. However, hclge_fetch_pf_reg does not distinguish the tqp space information when reading the tqp space information. When the number of TQPs is greater than 1024, access bar space overwriting occurs. The problem of different segments has been considered during the initialization of tqp.io_base. Therefore, tqp.io_base is directly used when the queue is read in hclge_fetch_pf_reg. The error message: Unable to handle kernel paging request at virtual address ffff800037200000 pc : hclge_fetch_pf_reg+0x138/0x250 [hclge] lr : hclge_get_regs+0x84/0x1d0 [hclge] Call trace: hclge_fetch_pf_reg+0x138/0x250 [hclge] hclge_get_regs+0x84/0x1d0 [hclge] hns3_get_regs+0x2c/0x50 [hns3] ethtool_get_regs+0xf4/0x270 dev_ethtool+0x674/0x8a0 dev_ioctl+0x270/0x36c sock_do_ioctl+0x110/0x2a0 sock_ioctl+0x2ac/0x530 __arm64_sys_ioctl+0xa8/0x100 invoke_syscall+0x4c/0x124 el0_svc_common.constprop.0+0x140/0x15c do_el0_svc+0x30/0xd0 el0_svc+0x1c/0x2c el0_sync_handler+0xb0/0xb4 el0_sync+0x168/0x180

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

The underlying weakness: Out-of-bounds Write

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

How developers prevent this class of flaw

  • Use a language that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. For example, many languages that perform their own memory management, such as Java and Perl, are not subject to buffer overflows. Other languages, such as Ada and C#, typically provide overflow protection, but the protection can be disabled by the programmer. Be wary that a language's interface to native code may still be subject to overflows, even if the language itself is theoretically safe.
  • Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. Examples include the Safe C String Library (SafeStr) by Messier and Viega, and the Strsafe.h library from Microsoft. These libraries provide safer versions of overflow-prone string-handling functions.
  • Use automatic buffer overflow detection mechanisms that are offered by certain compilers or compiler extensions. Examples include: the Microsoft Visual Studio /GS flag, Fedora/Red Hat FORTIFY_SOURCE GCC flag, StackGuard, and ProPolice, which provide various mechanisms including canary-based detection and range/index checking. D3-SFCV (Stack Frame Canary Validation) from D3FEND discusses canary-based detection in detail.

More Out-of-bounds Write vulnerabilities (CWE-787)

Timeline

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

References

Recent Out-of-bounds Write vulnerabilities

Spotted an error? Tell us.