CyberSecBulletin
CVE-2026-43075NVD status: Modified

Linux: Out-of-bounds Write

Published Updated By the CyberSecBulletin desk

CVE-2026-43075 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 68f9cc3bbf2ae501770cea7dc0005fc9a85e48ea, 2e6a254f9cedf51b75cc20b8b92e2209bfa04c3e, 22df7d4de9c5cd42edf855a1de25f2106088c4c6 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 0.13% 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 68f9cc3bbf2ae501770cea7dc0005fc9a85e48ea or 2e6a254f9cedf51b75cc20b8b92e2209bfa04c3e or 22df7d4de9c5cd42edf855a1de25f2106088c4c6 or e2c9dc6b6e96f3585f2a1062ca3374a52db0938f, whichever matches your release line, or a later version.
  2. Update Linux Kernel to 6.6.136 or 6.12.83 or 6.18.24 or 6.19.14, whichever matches your release line, or a later version.

Affected products and versions

VendorProductAffected versionsFixed in
LinuxLinux1afc32b952335f665327a1a9001ba1b44bb76fd9 up to, but not including, 68f9cc3bbf2ae501770cea7dc0005fc9a85e48ea; 1afc32b952335f665327a1a9001ba1b44bb76fd9 up to, but not including, 2e6a254f9cedf51b75cc20b8b92e2209bfa04c3e; 1afc32b952335f665327a1a9001ba1b44bb76fd9 up to, but not including, 22df7d4de9c5cd42edf855a1de25f2106088c4c6; 1afc32b952335f665327a1a9001ba1b44bb76fd9 up to, but not including, e2c9dc6b6e96f3585f2a1062ca3374a52db0938f; 1afc32b952335f665327a1a9001ba1b44bb76fd9 up to, but not including, 947f953978b0d9463498d548d0f054f5a75be2e9; 1afc32b952335f665327a1a9001ba1b44bb76fd9 up to, but not including, 0c1af902223b6fcedb60904ca0b551254686c7b9; 1afc32b952335f665327a1a9001ba1b44bb76fd9 up to, but not including, 69d3c69ade1e4285ab4ca48fe7acee0767e65604; 1afc32b952335f665327a1a9001ba1b44bb76fd9 up to, but not including, 7bc5da4842bed3252d26e742213741a4d0ac1b14; and 1 more ranges68f9cc3bbf2ae501770cea7dc0005fc9a85e48ea, 2e6a254f9cedf51b75cc20b8b92e2209bfa04c3e, 22df7d4de9c5cd42edf855a1de25f2106088c4c6, e2c9dc6b6e96f3585f2a1062ca3374a52db0938f, 947f953978b0d9463498d548d0f054f5a75be2e9, 0c1af902223b6fcedb60904ca0b551254686c7b9
LinuxLinux Kernel2.6.24.1 up to, but not including, 6.6.136; 6.7 up to, but not including, 6.12.83; 6.13 up to, but not including, 6.18.24; 6.19 up to, but not including, 6.19.14; 2.6.24; 7.06.6.136, 6.12.83, 6.18.24, 6.19.14

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 CNA.

Official description

In the Linux kernel, the following vulnerability has been resolved: ocfs2: fix out-of-bounds write in ocfs2_write_end_inline KASAN reports a use-after-free write of 4086 bytes in ocfs2_write_end_inline, called from ocfs2_write_end_nolock during a copy_file_range splice fallback on a corrupted ocfs2 filesystem mounted on a loop device. The actual bug is an out-of-bounds write past the inode block buffer, not a true use-after-free. The write overflows into an adjacent freed page, which KASAN reports as UAF. The root cause is that ocfs2_try_to_write_inline_data trusts the on-disk id_count field to determine whether a write fits in inline data. On a corrupted filesystem, id_count can exceed the physical maximum inline data capacity, causing writes to overflow the inode block buffer. Call trace (crash path): vfs_copy_file_range (fs/read_write.c:1634) do_splice_direct splice_direct_to_actor iter_file_splice_write ocfs2_file_write_iter generic_perform_write ocfs2_write_end ocfs2_write_end_nolock (fs/ocfs2/aops.c:1949) ocfs2_write_end_inline (fs/ocfs2/aops.c:1915) memcpy_from_folio <-- KASAN: write OOB So add id_count upper bound check in ocfs2_validate_inode_block() to alongside the existing i_size check to fix it.

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. Record last changed materially (score, affected products, status or references).

References

Recent Out-of-bounds Write vulnerabilities

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