CyberSecBulletin
CVE-2026-64548NVD status: Analyzed

Linux: Out-of-bounds Write

Published Updated By the CyberSecBulletin desk

CVE-2026-64548 is a high-severity out-of-bounds write vulnerability in Linux, with a CVSS 3.1 base score of 8.4 out of 10. It can be exploited with local access to the system by an unauthenticated attacker, without any action from a user. The record lists versions f1644c9508d24f50dd9e8ebe8d3ba86e0996d2f5, a12b1575f9feabd91695a9e9d004862f7195fa25, ff39d0e3b4feeb65ca43c453d7c75fdf872ded0d 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 0.14% 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 f1644c9508d24f50dd9e8ebe8d3ba86e0996d2f5 or a12b1575f9feabd91695a9e9d004862f7195fa25 or ff39d0e3b4feeb65ca43c453d7c75fdf872ded0d or 888706a76286c547bd035432602571e8024b5305, whichever matches your release line, or a later version.
  2. Update Linux Kernel to 5.10.261 or 5.15.212 or 6.1.178 or 6.6.145, whichever matches your release line, or a later version.

Affected products and versions

VendorProductAffected versionsFixed in
LinuxLinux6fff607e2f14bd7c63c06c464a6f93b8efbabe28 up to, but not including, f1644c9508d24f50dd9e8ebe8d3ba86e0996d2f5; 6fff607e2f14bd7c63c06c464a6f93b8efbabe28 up to, but not including, a12b1575f9feabd91695a9e9d004862f7195fa25; 6fff607e2f14bd7c63c06c464a6f93b8efbabe28 up to, but not including, ff39d0e3b4feeb65ca43c453d7c75fdf872ded0d; 6fff607e2f14bd7c63c06c464a6f93b8efbabe28 up to, but not including, 888706a76286c547bd035432602571e8024b5305; 6fff607e2f14bd7c63c06c464a6f93b8efbabe28 up to, but not including, db77b6bb6e6edb79b10b4efcce346eec5582d588; 6fff607e2f14bd7c63c06c464a6f93b8efbabe28 up to, but not including, 4e40056bb5c829f0423f0a6694a0477726d2147e; 6fff607e2f14bd7c63c06c464a6f93b8efbabe28 up to, but not including, bd004716ba75fed6d185795c85cdc92540ebeaab; 6fff607e2f14bd7c63c06c464a6f93b8efbabe28 up to, but not including, 0c0a8ed85349dae298712d79cb276acfeb794d82; and 1 more rangesf1644c9508d24f50dd9e8ebe8d3ba86e0996d2f5, a12b1575f9feabd91695a9e9d004862f7195fa25, ff39d0e3b4feeb65ca43c453d7c75fdf872ded0d, 888706a76286c547bd035432602571e8024b5305, db77b6bb6e6edb79b10b4efcce346eec5582d588, 4e40056bb5c829f0423f0a6694a0477726d2147e
LinuxLinux Kernel4.20 up to, but not including, 5.10.261; 5.11 up to, but not including, 5.15.212; 5.16 up to, but not including, 6.1.178; 6.2 up to, but not including, 6.6.145; 6.7 up to, but not including, 6.12.97; 6.13 up to, but not including, 6.18.40; 6.19 up to, but not including, 7.1.55.10.261, 5.15.212, 6.1.178, 6.6.145, 6.12.97, 6.18.40

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
NoneNo account or login is needed.
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:N/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: bpf, sockmap: reject overflowing copy + len in bpf_msg_push_data() When the scatterlist ring is full or nearly full, bpf_msg_push_data() enters a copy fallback path and computes copy + len for the page allocation size. Since len comes from BPF with arg3_type = ARG_ANYTHING and both are u32, a crafted len can wrap the sum to a small value, causing an undersized allocation followed by an out-of-bounds memcpy. BUG: unable to handle page fault for address: ffffed104089a402 Oops: Oops: 0000 [#1] SMP KASAN NOPTI Call Trace: __asan_memcpy (mm/kasan/shadow.c:105) bpf_msg_push_data (net/core/filter.c:2852 net/core/filter.c:2788) bpf_prog_9ed8b5711920a7d7+0x2e/0x36 sk_psock_msg_verdict (net/core/skmsg.c:934) tcp_bpf_sendmsg (net/ipv4/tcp_bpf.c:421 net/ipv4/tcp_bpf.c:584) __sys_sendto (net/socket.c:2206) do_syscall_64 (arch/x86/entry/syscall_64.c:94) entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130) Add an overflow check before the allocation.

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

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