Linux: Out-of-bounds Write
CVE-2025-38267 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 b8df8cb8f7eef52baa9ac5bf36a405ca67945a91, e018053632bad8ee0752242c7d2cffb0bbf45404, 4fc78a7c9ca994e1da5d3940704d4e8f0ea8c5e4 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 0.22% 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 b8df8cb8f7eef52baa9ac5bf36a405ca67945a91 or e018053632bad8ee0752242c7d2cffb0bbf45404 or 4fc78a7c9ca994e1da5d3940704d4e8f0ea8c5e4, whichever matches your release line, or a later version.
- Update Linux Kernel to 6.12.34 or 6.15.3, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | fe832be05a8eee5f1488cbcc2c562dd82d079fd6 up to, but not including, b8df8cb8f7eef52baa9ac5bf36a405ca67945a91; fe832be05a8eee5f1488cbcc2c562dd82d079fd6 up to, but not including, e018053632bad8ee0752242c7d2cffb0bbf45404; fe832be05a8eee5f1488cbcc2c562dd82d079fd6 up to, but not including, 4fc78a7c9ca994e1da5d3940704d4e8f0ea8c5e4; 6.10 | b8df8cb8f7eef52baa9ac5bf36a405ca67945a91, e018053632bad8ee0752242c7d2cffb0bbf45404, 4fc78a7c9ca994e1da5d3940704d4e8f0ea8c5e4 |
| Linux | Linux Kernel | 6.10 up to, but not including, 6.12.34; 6.13 up to, but not including, 6.15.3 | 6.12.34, 6.15.3 |
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.
Official description
In the Linux kernel, the following vulnerability has been resolved: ring-buffer: Do not trigger WARN_ON() due to a commit_overrun When reading a memory mapped buffer the reader page is just swapped out with the last page written in the write buffer. If the reader page is the same as the commit buffer (the buffer that is currently being written to) it was assumed that it should never have missed events. If it does, it triggers a WARN_ON_ONCE(). But there just happens to be one scenario where this can legitimately happen. That is on a commit_overrun. A commit overrun is when an interrupt preempts an event being written to the buffer and then the interrupt adds so many new events that it fills and wraps the buffer back to the commit. Any new events would then be dropped and be reported as "missed_events". In this case, the next page to read is the commit buffer and after the swap of the reader page, the reader page will be the commit buffer, but this time there will be missed events and this triggers the following warning: ------------[ cut here ]------------ WARNING: CPU: 2 PID: 1127 at kernel/trace/ring_buffer.c:7357 ring_buffer_map_get_reader+0x49a/0x780 Modules linked in: kvm_intel kvm irqbypass CPU: 2 UID: 0 PID: 1127 Comm: trace-cmd Not tainted 6.15.0-rc7-test-00004-g478bc2824b45-dirty #564 PREEMPT Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 RIP: 0010:ring_buffer_map_get_reader+0x49a/0x780 Code: 00 00 00 48 89 fe 48 c1 ee 03 80 3c 2e 00 0f 85 ec 01 00 00 4d 3b a6 a8 00 00 00 0f 85 8a fd ff ff 48 85 c0 0f 84 55 fe ff ff <0f> 0b e9 4e fe ff ff be 08 00 00 00 4c 89 54 24 58 48 89 54 24 50 RSP: 0018:ffff888121787dc0 EFLAGS: 00010002 RAX: 00000000000006a2 RBX: ffff888100062800 RCX: ffffffff8190cb49 RDX: ffff888126934c00 RSI: 1ffff11020200a15 RDI: ffff8881010050a8 RBP: dffffc0000000000 R08: 0000000000000000 R09: ffffed1024d26982 R10: ffff888126934c17 R11: ffff8881010050a8 R12: ffff888126934c00 R13: ffff8881010050b8 R14: ffff888101005000 R15: ffff888126930008 FS: 00007f95c8cd7540(0000) GS:ffff8882b576e000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f95c8de4dc0 CR3: 0000000128452002 CR4: 0000000000172ef0 Call Trace: <TASK> ? __pfx_ring_buffer_map_get_reader+0x10/0x10 tracing_buffers_ioctl+0x283/0x370 __x64_sys_ioctl+0x134/0x190 do_syscall_64+0x79/0x1c0 entry_SYSCALL_64_after_hwframe+0x76/0x7e RIP: 0033:0x7f95c8de48db Code: 00 48 89 44 24 18 31 c0 48 8d 44 24 60 c7 04 24 10 00 00 00 48 89 44 24 08 48 8d 44 24 20 48 89 44 24 10 b8 10 00 00 00 0f 05 <89> c2 3d 00 f0 ff ff 77 1c 48 8b 44 24 18 64 48 2b 04 25 28 00 00 RSP: 002b:00007ffe037ba110 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007ffe037bb2b0 RCX: 00007f95c8de48db RDX: 0000000000000000 RSI: 0000000000005220 RDI: 0000000000000006 RBP: 00007ffe037ba180 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffe037bb6f8 R14: 00007f95c9065000 R15: 00005575c7492c90 </TASK> irq event stamp: 5080 hardirqs last enabled at (5079): [<ffffffff83e0adb0>] _raw_spin_unlock_irqrestore+0x50/0x70 hardirqs last disabled at (5080): [<ffffffff83e0aa83>] _raw_spin_lock_irqsave+0x63/0x70 softirqs last enabled at (4182): [<ffffffff81516122>] handle_softirqs+0x552/0x710 softirqs last disabled at (4159): [<ffffffff815163f7>] __irq_exit_rcu+0x107/0x210 ---[ end trace 0000000000000000 ]--- The above was triggered by running on a kernel with both lockdep and KASAN as well as kmemleak enabled and executing the following command: # perf record -o perf-test.dat -a -- trace-cmd record --nosplice -e all -p function hackbench 50 With perf interjecting a lot of interrupts and trace-cmd enabling all events as well as function tracing, with lockdep, KASAN and kmemleak enabled, it could cause an interrupt preempting an event being written to add enough event ---truncated---
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.
Timeline
- CVE record published.
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
Recent Out-of-bounds Write vulnerabilities
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
Spotted an error? Tell us.