How severe is CVE-2025-21718?

CVE-2025-21718 has a CVSS 3.x base score of 7.0, rated high severity. It is exploitable over local access with high attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2025-21718 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (5th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2025-21718?

CVE-2025-21718 affects Linux Linux Kernel. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2025-21718?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

Does CVE-2025-21718 have an EU (EUVD) identifier?

Yes. CVE-2025-21718 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-5216.

When was CVE-2025-21718 published?

CVE-2025-21718 was published on 2025-02-27 and last updated on 2026-06-17.

CVE-2025-21718

CVE-2025-21718 is a high-severity vulnerability in Linux Linux Kernel with a CVSS 3.x base score of 7.0. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-362.

Key facts

Severity: High (CVSS 3.x base score 7.0)
EPSS exploit prediction: 0% (5th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2025-5216
Weakness: CWE-362
Affected product: Linux Linux Kernel
Published: 2025-02-27
Last modified: 2026-06-17

Description

In the Linux kernel, the following vulnerability has been resolved: net: rose: fix timer races against user threads Rose timers only acquire the socket spinlock, without checking if the socket is owned by one user thread. Add a check and rearm the timers if needed. BUG: KASAN: slab-use-after-free in rose_timer_expiry+0x31d/0x360 net/rose/rose_timer.c:174 Read of size 2 at addr ffff88802f09b82a by task swapper/0/0 CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Not tainted 6.13.0-rc5-syzkaller-00172-gd1bf27c4e176 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024 Call Trace: <IRQ> __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:378 [inline] print_report+0x169/0x550 mm/kasan/report.c:489 kasan_report+0x143/0x180 mm/kasan/report.c:602 rose_timer_expiry+0x31d/0x360 net/rose/rose_timer.c:174 call_timer_fn+0x187/0x650 kernel/time/timer.c:1793 expire_timers kernel/time/timer.c:1844 [inline] __run_timers kernel/time/timer.c:2418 [inline] __run_timer_base+0x66a/0x8e0 kernel/time/timer.c:2430 run_timer_base kernel/time/timer.c:2439 [inline] run_timer_softirq+0xb7/0x170 kernel/time/timer.c:2449 handle_softirqs+0x2d4/0x9b0 kernel/softirq.c:561 __do_softirq kernel/softirq.c:595 [inline] invoke_softirq kernel/softirq.c:435 [inline] __irq_exit_rcu+0xf7/0x220 kernel/softirq.c:662 irq_exit_rcu+0x9/0x30 kernel/softirq.c:678 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1049 [inline] sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1049 </IRQ>

Frequently asked questions

What is CVE-2025-21718?: In the Linux kernel, the following vulnerability has been resolved: net: rose: fix timer races against user threads Rose timers only acquire the socket spinlock, without checking if the socket is owned by one user thread. Add a check and rearm the timers if needed. BUG: KASAN: slab-use-after-free in rose_timer_expiry+0x31d/0x360 net/rose/rose_timer.c:174 Read of size 2 at addr ffff88802f09b82a by task swapper/0/0 CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Not tainted 6.13.0-rc5-syzkaller-00172-gd1bf27c4e176 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024 Call Trace: <IRQ> __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:378 [inline] print_report+0x169/0x550 mm/kasan/report.c:489 kasan_report+0x143/0x180 mm/kasan/report.c:602 rose_timer_expiry+0x31d/0x360 net/rose/rose_timer.c:174 call_timer_fn+0x187/0x650 kernel/time/timer.c:1793 expire_timers kernel/time/timer.c:1844 [inline] __run_timers kernel/time/timer.c:2418 [inline] __run_timer_base+0x66a/0x8e0 kernel/time/timer.c:2430 run_timer_base kernel/time/timer.c:2439 [inline] run_timer_softirq+0xb7/0x170 kernel/time/timer.c:2449 handle_softirqs+0x2d4/0x9b0 kernel/softirq.c:561 __do_softirq kernel/softirq.c:595 [inline] invoke_softirq kernel/softirq.c:435 [inline] __irq_exit_rcu+0xf7/0x220 kernel/softirq.c:662 irq_exit_rcu+0x9/0x30 kernel/softirq.c:678 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1049 [inline] sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1049 </IRQ>
How severe is CVE-2025-21718?: CVE-2025-21718 has a CVSS 3.x base score of 7.0, rated high severity. It is exploitable over local access with high attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2025-21718 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (5th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2025-21718?: CVE-2025-21718 affects Linux Linux Kernel. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2025-21718?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2025-21718 have an EU (EUVD) identifier?: Yes. CVE-2025-21718 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-5216.
When was CVE-2025-21718 published?: CVE-2025-21718 was published on 2025-02-27 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*

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