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CVE-2026-23159— perf: sched: Fix perf crash with new is_user_task() helper

Quick assessment

Affected
Linux Linux
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

Linux kernel是美国Linux基金会的开源操作系统Linux所使用的内核。 Linux kernel存在安全漏洞，该漏洞源于is_user_task辅助函数检查不当，可能导致性能分析器崩溃。

AI Predicted 5.5 Difficulty: Moderate EPSS 0.13% · P3

Affected Version Matrix 14

VendorProduct Version RangeStatus
Linux Linux 34b5aba8511a12fb2e9bd3124835cb4087187dac< d84a4836dc246b7dc244e46a08ff992956b68db0 affected
8d79f96e477c4b8e3fca2efb36b269d8960a2285< 5aac392fcd3d981d7997f1a0766829e1afdeac2e affected
90942f9fac05702065ff82ed0bade0d08168d4ea< a28fce0365e1cb9cb8c04c893b9334e5ca9d9f1c affected
90942f9fac05702065ff82ed0bade0d08168d4ea< 76ed27608f7dd235b727ebbb12163438c2fbb617 affected
5050083e1a2f3e5e29cee0205c40e5864b52601d affected
6.6.116< 6.6.123 affected
6.12.57< 6.12.69 affected
6.17.7< 6.18 affected
… +6 more rows
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I. Basic Information for CVE-2026-23159

Vulnerability Information
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Vulnerability Title
perf: sched: Fix perf crash with new is_user_task() helper
Source: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved: perf: sched: Fix perf crash with new is_user_task() helper In order to do a user space stacktrace the current task needs to be a user task that has executed in user space. It use to be possible to test if a task is a user task or not by simply checking the task_struct mm field. If it was non NULL, it was a user task and if not it was a kernel task. But things have changed over time, and some kernel tasks now have their own mm field. An idea was made to instead test PF_KTHREAD and two functions were used to wrap this check in case it became more complex to test if a task was a user task or not[1]. But this was rejected and the C code simply checked the PF_KTHREAD directly. It was later found that not all kernel threads set PF_KTHREAD. The io-uring helpers instead set PF_USER_WORKER and this needed to be added as well. But checking the flags is still not enough. There's a very small window when a task exits that it frees its mm field and it is set back to NULL. If perf were to trigger at this moment, the flags test would say its a user space task but when perf would read the mm field it would crash with at NULL pointer dereference. Now there are flags that can be used to test if a task is exiting, but they are set in areas that perf may still want to profile the user space task (to see where it exited). The only real test is to check both the flags and the mm field. Instead of making this modification in every location, create a new is_user_task() helper function that does all the tests needed to know if it is safe to read the user space memory or not. [1] https://lore.kernel.org/all/20250425204120.639530125@goodmis.org/
Source: CVE Program / CVE List V5
CVSS Information
N/A
Source: CVE Program / CVE List V5
Vulnerability Type
N/A
Source: CVE Program / CVE List V5
Vulnerability Title
Linux kernel 安全漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
Linux kernel是美国Linux基金会的开源操作系统Linux所使用的内核。 Linux kernel存在安全漏洞，该漏洞源于is_user_task辅助函数检查不当，可能导致性能分析器崩溃。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

Vendor Product Affected Versions CPE Subscribe
Linux Linux 34b5aba8511a12fb2e9bd3124835cb4087187dac ~ d84a4836dc246b7dc244e46a08ff992956b68db0 -
Linux Linux 6.18 -

II. Public POCs for CVE-2026-23159

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III. Intelligence Information for CVE-2026-23159

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Same Patch Batch · Linux · 2026-02-14 · 108 CVEs total

CVE-2025-71202 8.8 HIGH iommu/sva: invalidate stale IOTLB entries for kernel address space
CVE-2026-23193 8.8 HIGH scsi: target: iscsi: Fix use-after-free in iscsit_dec_session_usage_count()
CVE-2026-23172 8.4 HIGH net: wwan: t7xx: fix potential skb->frags overflow in RX path
CVE-2026-23209 7.8 HIGH macvlan: fix error recovery in macvlan_common_newlink()
CVE-2025-71221 7.8 HIGH dmaengine: mmp_pdma: Fix race condition in mmp_pdma_residue()
CVE-2026-23178 7.8 HIGH HID: i2c-hid: fix potential buffer overflow in i2c_hid_get_report()
CVE-2026-23184 7.8 HIGH binder: fix UAF in binder_netlink_report()
CVE-2026-23185 7.8 HIGH wifi: iwlwifi: mld: cancel mlo_scan_start_wk
CVE-2026-23171 7.8 HIGH bonding: fix use-after-free due to enslave fail after slave array update
CVE-2026-23169 7.8 HIGH mptcp: fix race in mptcp_pm_nl_flush_addrs_doit()
CVE-2026-23191 7.8 HIGH ALSA: aloop: Fix racy access at PCM trigger
CVE-2026-23192 7.8 HIGH linkwatch: use __dev_put() in callers to prevent UAF
CVE-2026-23198 7.8 HIGH KVM: Don't clobber irqfd routing type when deassigning irqfd
CVE-2026-23136 7.5 HIGH libceph: reset sparse-read state in osd_fault()
CVE-2026-23148 7.5 HIGH nvmet: fix race in nvmet_bio_done() leading to NULL pointer dereference
CVE-2026-23139 7.5 HIGH netfilter: nf_conncount: update last_gc only when GC has been performed
CVE-2025-71204 7.5 HIGH smb/server: fix refcount leak in parse_durable_handle_context()
CVE-2026-23161 7.3 HIGH mm/shmem, swap: fix race of truncate and swap entry split
CVE-2026-23204 7.1 HIGH net/sched: cls_u32: use skb_header_pointer_careful()
CVE-2025-71201 7.1 HIGH netfs: Fix early read unlock of page with EOF in middle

Showing top 20 of 108 CVEs. View all on vendor page &rarr; →

IV. Related Vulnerabilities

Same product: Linux
Same vendor: Linux

V. Comments for CVE-2026-23159

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