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CVE-2026-74749— rseq: Prevent hard lockup on granted time slice extension

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，以下漏洞已得到修复： rseq：防止因批准时间片扩展导致的硬锁死 在启用中断的情况下调用 。如果时间片扩展被批准，它会调用 ，以确保在退出到用户空间之前，处理任何待处理的延迟高分辨率定时器（hrtimer）重新武装操作。 然而，该调用触发了 ，而后者期望在中断被禁用的情况下被调用，因为它使用 获取 。这种在中断启用状态下操作需要在中断禁用时才能安全获取的锁，极易引发活锁（livelock），并已被 lockdep 捕获到如下警告： 修复方式：在 中，在调用 时禁用中断，从而避免上述锁状态不一

AI Predicted 5.5 Difficulty: Hard EPSS 0.16% · P6

Possible ATT&CK Techniques 1 AI

T1059 · Command and Scripting Interpreter

Affected Version Matrix 6

VendorProduct Version RangeStatus
Linux Linux 15dd3a9488557d3e6ebcecacab79f4e56b69ab54< 8bbf4405050bc4f98be68082a20efa081ea8ad9b affected
15dd3a9488557d3e6ebcecacab79f4e56b69ab54< ada54c2ba652348c590d1ace6a2f4ff77cbbf809 affected
7.1 affected
< 7.1 unaffected
7.1.10≤ 7.1.* unaffected
7.2≤ * unaffected
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I. Basic Information for CVE-2026-74749

Vulnerability Information
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Vulnerability Title
rseq: Prevent hard lockup on granted time slice extension
Source: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved: rseq: Prevent hard lockup on granted time slice extension __exit_to_user_mode_loop() invokes rseq_grant_timeslice_extension() with interrupts enabled. If the extension is granted it invokes hrtimer_rearm_deferred_tif() to ensure that a pending deferred hrtimer rearm is handled before exiting to user space. Though this invokes __hrtimer_rearm_deferred() which expects to be invoked with interrupts disabled as it takes hrtimer_cpu_base::lock with raw_spin_lock(). That's a livelock waiting to happen and caught by lockdep: WARNING: ./include/linux/hrtimer_rearm.h:17 at irqentry_exit, CPU#1: slice_test WARNING: inconsistent lock state inconsistent {IN-HARDIRQ-W} -> {HARDIRQ-ON-W} usage. Prevent this by disabling interrupts around the invocation of hrtimer_rearm_deferred_tif() in rseq_grant_timeslice_extension(). [ tglx: Massaged change log ]
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 15dd3a9488557d3e6ebcecacab79f4e56b69ab54 ~ 8bbf4405050bc4f98be68082a20efa081ea8ad9b -
Linux Linux 7.1 -

II. Public POCs for CVE-2026-74749

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III. Intelligence Information for CVE-2026-74749

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Patches & Fixes for CVE-2026-74749 (2)

Same Patch Batch · Linux · 2026-08-26 · 92 CVEs total

CVE-2026-80558 9.8 CRITICAL libceph: Avoid using invalid osd indices from primary_temp
CVE-2026-74752 9.8 CRITICAL sctp: validate cookie AUTH state before use
CVE-2026-74746 9.8 CRITICAL netfilter: flowtable: publish GC-visible tuple last
CVE-2026-80519 9.8 CRITICAL ovpn: finish crypto callback cleanup before peer release
CVE-2026-74744 9.8 CRITICAL ipvlan: inherit needed_headroom and needed_tailroom from phy_dev
CVE-2026-74743 9.8 CRITICAL macvlan: inherit needed_headroom and needed_tailroom from lowerdev
CVE-2026-80557 9.8 CRITICAL libceph: fix OOB read in decode_watchers() via missing bounds check
CVE-2026-80586 9.8 CRITICAL mptcp: options: reset DSS fields in case of unexpected size
CVE-2026-80587 9.8 CRITICAL mptcp: avoid combining some incoming suboptions
CVE-2026-80561 9.8 CRITICAL libceph: fix multiple unsafe decodes in decode_locker()
CVE-2026-74737 9.8 CRITICAL net: ethernet: ti: am65-cpsw-nuss: Fix port_id extraction from SRC TAG
CVE-2026-80589 9.8 CRITICAL block: stop the timeout timer when releasing a never added disk
CVE-2026-80528 9.8 CRITICAL ceph: avoid fs reclaim while using current->journal_info
CVE-2026-80585 9.4 CRITICAL mptcp: fastopen: only mark MPTFO subflows with SYN data
CVE-2026-74751 9.4 CRITICAL riscv: lib: Fix ZBB strnlen reading past count boundary
CVE-2026-80554 9.3 CRITICAL s390/vfio_ccw: Limit the number of channel program segments
CVE-2026-80551 9.3 CRITICAL s390/vfio_ccw: Ensure first IDAW remains constant
CVE-2026-80576 8.8 HIGH drm/amdgpu: reject oversized IBs with per-ring packet limits
CVE-2026-80547 8.8 HIGH s390/vfio_ccw: Implement a crw lock
CVE-2026-80548 8.8 HIGH s390/vfio_ccw: Selectively expand io_mutex

Showing top 20 of 92 CVEs. View all on vendor page &rarr; →

IV. Related Vulnerabilities

Same product: Linux
Same vendor: Linux

V. Comments for CVE-2026-74749

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