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CVE-2026-97938— reboot: fix cad_pid use-after-free race

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.

在 Linux 内核中，已修复以下漏洞： reboot：修复 cad_pid 的使用后释放（use-after-free）竞争条件 是一个全局单一的 指针。 函数在读取该指针后，会将其传递给 ，但在此过程中并未保护所引用 的生命周期。如果并发写入者在该指针被读取之后、但在 完成解引用之前，替换了 并对旧的 释放了最后一个引用，就会导致使用-after-free 错误。 在将 传递给 时，也存在相同的生命周期竞争问题。 在该问题被报告时，由于 被注册在 中，非特权用户可以通过用户命名空间和 PID 命名空间访问该 s

AI Predicted 7.8 Difficulty: Moderate EPSS 0.20% · P9

Possible ATT&CK Techniques 1 AI

T1068 · Exploitation for Privilege Escalation

Affected Version Matrix 10

VendorProduct Version RangeStatus
Linux Linux 9ec52099e4b8678a60e9f93e41ad87885d64f3e6< ae3e53fe3c1241855e3a88f74877738349948c78 affected
9ec52099e4b8678a60e9f93e41ad87885d64f3e6< ad72e2566643fff7f01666d845fb026898155e1f affected
9ec52099e4b8678a60e9f93e41ad87885d64f3e6< 9a17b0e053197a6a42cdc75e75a35b17aa662088 affected
9ec52099e4b8678a60e9f93e41ad87885d64f3e6< 5a88f78df753993469dab4d1831f8fb4256a9468 affected
2.6.19 affected
< 2.6.19 unaffected
6.12.112≤ 6.12.* unaffected
6.18.53≤ 6.18.* unaffected
… +2 more rows
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I. Basic Information for CVE-2026-97938

Vulnerability Information
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Vulnerability Title
reboot: fix cad_pid use-after-free race
Source: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved: reboot: fix cad_pid use-after-free race cad_pid is a single kernel-wide struct pid pointer. proc_do_cad_pid() reads it and passes it to pid_vnr() without protecting the lifetime of the referenced struct pid. A concurrent writer can replace cad_pid and drop the final reference to the old struct pid after the reader has loaded the pointer but before pid_vnr() has finished dereferencing it, causing a use-after-free. kill_cad_pid() has the same lifetime race when it passes cad_pid to kill_pid(). At the time this issue was reported, an unprivileged user could reach the sysctl through user and PID namespaces because cad_pid was registered in pid_table[]. Moving cad_pid back to the global reboot sysctl table corrected that namespace and permission mismatch, but did not fix the underlying lifetime race. Fix this by treating cad_pid as an RCU-protected pointer at both read sites and by waiting for a grace period before dropping the old reference on the write side. call_rcu(&old_pid->rcu, ...) cannot be used here because free_pid() also queues pid->rcu; queueing the same rcu_head twice can corrupt the RCU callback list. Original KASAN crash stack: kernel/pid.c:545 pid_nr_ns() # reads freed pid->level kernel/pid.c:556 pid_vnr() # calls pid_nr_ns() kernel/pid.c:775 proc_do_cad_pid() # calls pid_vnr(cad_pid)
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

Affected Products

Vendor Product Affected Versions CPE Subscribe
Linux Linux 9ec52099e4b8678a60e9f93e41ad87885d64f3e6 ~ ae3e53fe3c1241855e3a88f74877738349948c78 -
Linux Linux 2.6.19 -

II. Public POCs for CVE-2026-97938

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III. Intelligence Information for CVE-2026-97938

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Patches & Fixes for CVE-2026-97938 (4)

Same Patch Batch · Linux · 2026-09-25 · 372 CVEs total

CVE-2026-100075 9.8 CRITICAL RDMA/srpt: Fix srpt_alloc_rw_ctxs() unwind counters
CVE-2026-97555 8.8 HIGH smb: client: fix heap overflow in DACL owner/group rewrite
CVE-2026-97957 8.8 HIGH net: hinic: fix mailbox segment buffer overflow
CVE-2026-97527 8.8 HIGH scsi: qla2xxx: Serialize NVMe unsol ctx list with a per-fcport lock
CVE-2026-97528 8.8 HIGH scsi: qla2xxx: Unlink NVMe unsol ctx before freeing on LS reject error
CVE-2026-98115 8.8 HIGH ksmbd: safely drain sessions during logoff
CVE-2026-97525 8.2 HIGH x86/mm/pat: Allocate split page tables as kernel page tables
CVE-2026-98069 8.1 HIGH net/rds: acquire the fastpath locks in rds_conn_shutdown()
CVE-2026-97573 8.1 HIGH bnxt_en: Handle buffer allocation failure in bnxt_rx_ring_reset()
CVE-2026-97570 8.1 HIGH bnxt_en: Bound SW TPA IDs to prevent crashes
CVE-2026-98130 8.1 HIGH sctp: fix a TOCTOU race in SCTP_CMD_TIMER_START
CVE-2026-98070 8.1 HIGH net/rds: acquire RDS_IN_XMIT in rds_tcp_reset_callbacks()
CVE-2026-98122 7.8 HIGH vxlan: mdb: Fix use-after-free in vxlan_mdb_remote_src_del()
CVE-2026-97575 7.8 HIGH media: v4l2-ctrls: validate AV1 tile counts
CVE-2026-97576 7.8 HIGH media: v4l2-ctrls: validate HEVC tile counts
CVE-2026-98112 7.8 HIGH ksmbd: fix listener task lifetime on netdev events
CVE-2026-98002 7.8 HIGH iommu/amd: Fix ineffective error check in nested domain allocation
CVE-2026-97937 7.8 HIGH ftrace: fork: Initialize function graph state before copy_exec_state()
CVE-2026-97580 7.8 HIGH media: rkvdec: bound HEVC tile loops and PPS id to the array capacity
CVE-2026-97940 7.8 HIGH ipv6: fix fib6 walker UAF on seq stop

Showing top 20 of 372 CVEs. View all on vendor page &rarr; →

IV. Related Vulnerabilities

Same product: Linux
Same vendor: Linux

V. Comments for CVE-2026-97938

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