5.5

CVE-2026-64250: LoongArch: Report dying CPU to RCU in stop_this_cpu()

Analyzed
AliasesUBUNTU-CVE-2026-64250DEBIAN-CVE-2026-64250
Published 24-07-2026Last modified 17-08-2026

Vulnerability summary

CVE-2026-64250 is a medium (CVSS 5.5) vulnerability in linux. EPSS estimates a 0.16% chance of exploitation in the next 30 days, higher than 4.9% of scored vulnerabilities.

Priority
Routine

Not severe (CVSS 5.5, local access); no exploitation reported by the 5 checked sources

Source freshness unavailable

How is this decided?
CVSS score
5.5/10
010
Medium · v3.1 (NVD)
EPSS score
0.16%
0%100%
Low · 0.00 pp in 30 days
KEVNot listedNot listed by any tracked catalog.
RansomwareNot flaggedNo ransomware use recorded.
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 1 · Related 1
OPENSUSE-SU-2026:11476-1

Timeline

  1. 24-07-2026
    PublishedVulnerability first disclosed.
  2. 17-08-2026
    Last modifiedVulnerability information updated.

Description

In the Linux kernel, the following vulnerability has been resolved: LoongArch: Report dying CPU to RCU in stop_this_cpu() This is a port of MIPS commit 9f3f3bdc6d9dac1 ("MIPS: smp: report dying CPU to RCU in stop_this_cpu()"). smp_send_stop() parks all secondary CPUs in stop_this_cpu(). And the function marks the CPU offline for the scheduler via set_cpu_online(false) but never informs RCU, so RCU keeps expecting a quiescent state from CPUs that are now spinning forever with interrupts disabled. As long as nothing waits for an RCU grace period after smp_send_stop() this is harmless, which is why it went unnoticed. However, since commit 91840be8f710370 ("irq_work: Fix use-after-free in irq_work_single() on PREEMPT_RT"), irq_work_sync() calls synchronize_rcu() on architectures without an irq_work self-IPI, i.e. where arch_irq_work_has_interrupt() returns false. Any irq_work_sync() issued in the reboot/shutdown/halt path after smp_send_stop() then blocks on a grace period that can never complete, hanging the reboot: WARNING: CPU: 0 PID: 15 at kernel/irq_work.c:144 irq_work_queue_on ... rcu: INFO: rcu_sched detected stalls on CPUs/tasks: rcu: Offline CPU 1 blocking current GP. rcu: Offline CPU 2 blocking current GP. rcu: Offline CPU 3 blocking current GP. This issue needs some hacks to reproduce, and it was not noticed on LoongArch because arch_irq_work_has_interrupt() usually returns true. Call rcutree_report_cpu_dead() once interrupts are disabled, mirroring the generic CPU-hotplug offline path, so RCU stops waiting on the parked CPUs and grace periods can still complete. LoongArch shuts down all CPUs here without going through the CPU-hotplug mechanism, so this report is not otherwise issued.

CVSS metrics

3 scores · 3 sources · 1 version

EPSS trend

Probability

0.16%

Chance of exploitation in the next 30 days

Percentile

5%

Versus all other CVEs

30-day change

No change 0.00 pp

From 0.16% on 04-10-2026

04-10-202603-11-2026

Known exploited

Compare KEV catalogs
CISA KEV

Not in the CISA KEV catalog.

ENISA CNW

Not in the ENISA CNW catalog.

CIRCL

Not in the CIRCL catalog.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

No weakness data has been published for this record.

Affected systems

Version check

Known conditions: local access, low-privilege account, no user interaction (CVSS vector). Other conditions: not stated in public data.

Ubuntu96 products
  • linux-allwinner-5.19All versions (No fix recorded)
  • linux-aws-5.0All versions (No fix recorded)
  • linux-aws-5.11All versions (No fix recorded)
  • linux-aws-5.13All versions (No fix recorded)
  • linux-aws-5.19All versions (No fix recorded)
Linux2 products
  • linux≥ 2dc79362302922cb18f35e262712b5e58de65442, < 262dadc619e69ebeb97affd334cd1078a9704e98 | ≥ eef4f71b46a9929ac33e968538c9dd5d96a02460, < 1fa22de588a65880d6fe54c38c87fffe7d519f60 | ≥ 684a78183c54c23e70d1cba320f7fc184604210b, < a0269e928728f970c782319fee53d92d4ea4e512 | ≥ 18c0456ea2615b1a743a6db739c74411c3b42bc6, < 90e254f18b8c224460082329dd5c42fd30995c2f | ≥ 91840be8f710370607f949a627e070896faeddb8, < 0833b2b84c2fc1387f8165f0cbf6a02d67f647a5 | ≥ 91840be8f710370607f949a627e070896faeddb8, < f2539c56c74691e7a88af6372ba2b48c06ed2fe4 | 81b582784518196eff1050212a046bc29d3a05dd | ≥ 6.1.175, < 6.1.178 | ≥ 6.6.142, < 6.6.145 | ≥ 6.12.92, < 6.12.95 | ≥ 6.18.34, < 6.18.38 | ≥ 7.0.11, < 7.1 | 7.1
  • linux_kernelEOL≥ 6.1.175, < 6.1.178 | ≥ 6.6.142, < 6.6.145 | ≥ 6.12.92, < 6.12.95 | ≥ 6.18.34, < 6.18.38 | ≥ 7.0.11, < 7.1 | ≥ 7.1.1, < 7.1.3 | 7.1 | 7.1:rc4 | 7.1:rc5 | 7.1:rc6 | 7.1:rc7
Debian1 product
  • linux< 6.1.180-1 | < 6.12.95-1 | < 7.1.3-1

3 vendors · 99 products

References

11 links
Show all 11 references