Linux: Out-of-bounds Read
CVE-2026-45957 is a high-severity out-of-bounds read vulnerability in Linux, with a CVSS 3.1 base score of 7.1 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 d36d8a7cf0e1d52ccde290855782b7b2ffc78f63, 979c708e6c9d7fc461daef2dad8b45f22e23464c, 1f16679a5aa60238466ce339c35f5e82ece60337 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.
High severity with no evidence of exploitation so far.
What to do
- Update Linux to d36d8a7cf0e1d52ccde290855782b7b2ffc78f63 or 979c708e6c9d7fc461daef2dad8b45f22e23464c or 1f16679a5aa60238466ce339c35f5e82ece60337 or 4a4a6e12c9c829be3f74b7206fa8640fc4e1c566, whichever matches your release line, or a later version.
- Update Linux Kernel to 6.6.128 or 6.12.75 or 6.18.14 or 6.19.4, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | 5f5fa7ea89dc82d34ed458f4d7a8634e8e9eefce up to, but not including, d36d8a7cf0e1d52ccde290855782b7b2ffc78f63; 5f5fa7ea89dc82d34ed458f4d7a8634e8e9eefce up to, but not including, 979c708e6c9d7fc461daef2dad8b45f22e23464c; 5f5fa7ea89dc82d34ed458f4d7a8634e8e9eefce up to, but not including, 1f16679a5aa60238466ce339c35f5e82ece60337; 5f5fa7ea89dc82d34ed458f4d7a8634e8e9eefce up to, but not including, 4a4a6e12c9c829be3f74b7206fa8640fc4e1c566; 5f5fa7ea89dc82d34ed458f4d7a8634e8e9eefce up to, but not including, c2932e16d8c354404b17123e64daa8e33191e145; 5f5fa7ea89dc82d34ed458f4d7a8634e8e9eefce up to, but not including, d41e37f26b3157b3f1d10223863519a943aa239b; 5.8 | d36d8a7cf0e1d52ccde290855782b7b2ffc78f63, 979c708e6c9d7fc461daef2dad8b45f22e23464c, 1f16679a5aa60238466ce339c35f5e82ece60337, 4a4a6e12c9c829be3f74b7206fa8640fc4e1c566, c2932e16d8c354404b17123e64daa8e33191e145, d41e37f26b3157b3f1d10223863519a943aa239b |
| Linux | Linux Kernel | 5.8 up to, but not including, 6.6.128; 6.7 up to, but not including, 6.12.75; 6.13 up to, but not including, 6.18.14; 6.19 up to, but not including, 6.19.4 | 6.6.128, 6.12.75, 6.18.14, 6.19.4 |
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
- NoneNothing can be modified.
- 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:N/A:H. Scored by NVD.
Official description
In the Linux kernel, the following vulnerability has been resolved: rcu: Fix rcu_read_unlock() deadloop due to softirq Commit 5f5fa7ea89dc ("rcu: Don't use negative nesting depth in __rcu_read_unlock()") removes the recursion-protection code from __rcu_read_unlock(). Therefore, we could invoke the deadloop in raise_softirq_irqoff() with ftrace enabled as follows: WARNING: CPU: 0 PID: 0 at kernel/trace/trace.c:3021 __ftrace_trace_stack.constprop.0+0x172/0x180 Modules linked in: my_irq_work(O) CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Tainted: G O 6.18.0-rc7-dirty #23 PREEMPT(full) Tainted: [O]=OOT_MODULE Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014 RIP: 0010:__ftrace_trace_stack.constprop.0+0x172/0x180 RSP: 0018:ffffc900000034a8 EFLAGS: 00010002 RAX: 0000000000000000 RBX: 0000000000000004 RCX: 0000000000000000 RDX: 0000000000000003 RSI: ffffffff826d7b87 RDI: ffffffff826e9329 RBP: 0000000000090009 R08: 0000000000000005 R09: ffffffff82afbc4c R10: 0000000000000008 R11: 0000000000011d7a R12: 0000000000000000 R13: ffff888003874100 R14: 0000000000000003 R15: ffff8880038c1054 FS: 0000000000000000(0000) GS:ffff8880fa8ea000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055b31fa7f540 CR3: 00000000078f4005 CR4: 0000000000770ef0 PKRU: 55555554 Call Trace: <IRQ> trace_buffer_unlock_commit_regs+0x6d/0x220 trace_event_buffer_commit+0x5c/0x260 trace_event_raw_event_softirq+0x47/0x80 raise_softirq_irqoff+0x6e/0xa0 rcu_read_unlock_special+0xb1/0x160 unwind_next_frame+0x203/0x9b0 __unwind_start+0x15d/0x1c0 arch_stack_walk+0x62/0xf0 stack_trace_save+0x48/0x70 __ftrace_trace_stack.constprop.0+0x144/0x180 trace_buffer_unlock_commit_regs+0x6d/0x220 trace_event_buffer_commit+0x5c/0x260 trace_event_raw_event_softirq+0x47/0x80 raise_softirq_irqoff+0x6e/0xa0 rcu_read_unlock_special+0xb1/0x160 unwind_next_frame+0x203/0x9b0 __unwind_start+0x15d/0x1c0 arch_stack_walk+0x62/0xf0 stack_trace_save+0x48/0x70 __ftrace_trace_stack.constprop.0+0x144/0x180 trace_buffer_unlock_commit_regs+0x6d/0x220 trace_event_buffer_commit+0x5c/0x260 trace_event_raw_event_softirq+0x47/0x80 raise_softirq_irqoff+0x6e/0xa0 rcu_read_unlock_special+0xb1/0x160 unwind_next_frame+0x203/0x9b0 __unwind_start+0x15d/0x1c0 arch_stack_walk+0x62/0xf0 stack_trace_save+0x48/0x70 __ftrace_trace_stack.constprop.0+0x144/0x180 trace_buffer_unlock_commit_regs+0x6d/0x220 trace_event_buffer_commit+0x5c/0x260 trace_event_raw_event_softirq+0x47/0x80 raise_softirq_irqoff+0x6e/0xa0 rcu_read_unlock_special+0xb1/0x160 __is_insn_slot_addr+0x54/0x70 kernel_text_address+0x48/0xc0 __kernel_text_address+0xd/0x40 unwind_get_return_address+0x1e/0x40 arch_stack_walk+0x9c/0xf0 stack_trace_save+0x48/0x70 __ftrace_trace_stack.constprop.0+0x144/0x180 trace_buffer_unlock_commit_regs+0x6d/0x220 trace_event_buffer_commit+0x5c/0x260 trace_event_raw_event_softirq+0x47/0x80 __raise_softirq_irqoff+0x61/0x80 __flush_smp_call_function_queue+0x115/0x420 __sysvec_call_function_single+0x17/0xb0 sysvec_call_function_single+0x8c/0xc0 </IRQ> Commit b41642c87716 ("rcu: Fix rcu_read_unlock() deadloop due to IRQ work") fixed the infinite loop in rcu_read_unlock_special() for IRQ work by setting a flag before calling irq_work_queue_on(). We fix this issue by setting the same flag before calling raise_softirq_irqoff() and rename the flag to defer_qs_pending for more common.
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/1f16679a5aa60238466ce339c35f5e82ece60337
- git.kernel.org/stable/c/4a4a6e12c9c829be3f74b7206fa8640fc4e1c566
- git.kernel.org/stable/c/979c708e6c9d7fc461daef2dad8b45f22e23464c
- git.kernel.org/stable/c/c2932e16d8c354404b17123e64daa8e33191e145
- git.kernel.org/stable/c/d41e37f26b3157b3f1d10223863519a943aa239b
Other references
Recent Out-of-bounds Read vulnerabilities
- 7.1 High severity
- 7.1 High severity
- 7.1 High severity
- 7.1 High severity
- 8.2 High severity
- 7.1 High severity
Spotted an error? Tell us.