VulnSocial

CVE-2026-43121General(linux / linux_kernel)

LOWCVSS 4.7 · MEDIUM

Signal is active with 1 mentions in latest observed window

Immediate actions

  • Track advisory updates for patch or workaround availability

Recommended action window: Monitor and triage in normal cycle

NVD description

In the Linux kernel, the following vulnerability has been resolved: io_uring/zcrx: fix user_ref race between scrub and refill paths The io_zcrx_put_niov_uref() function uses a non-atomic check-then-decrement pattern (atomic_read followed by separate atomic_dec) to manipulate user_refs. This is serialized against other callers by rq_lock, but io_zcrx_scrub() modifies the same counter with atomic_xchg() WITHOUT holding rq_lock. On SMP systems, the following race exists: CPU0 (refill, holds rq_lock) CPU1 (scrub, no rq_lock) put_niov_uref: atomic_read(uref) - 1 // window opens atomic_xchg(uref, 0) - 1 return_niov_freelist(niov) [PUSH #1] // window closes atomic_dec(uref) - wraps to -1 returns true return_niov(niov) return_niov_freelist(niov) [PUSH #2: DOUBLE-FREE] The same niov is pushed to the freelist twice, causing free_count to exceed nr_iovs. Subsequent freelist pushes then perform an out-of-bounds write (a u32 value) past the kvmalloc'd freelist array into the adjacent slab object. Fix this by replacing the non-atomic read-then-dec in io_zcrx_put_niov_uref() with an atomic_try_cmpxchg loop that atomically tests and decrements user_refs. This makes the operation safe against concurrent atomic_xchg from scrub without requiring scrub to acquire rq_lock. [pavel: removed a warning and a comment]

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0.0/ 10 priority

Sources & remediation

Patch / fix
Weakness type (CWE)
CWE-362

Priority

LOW

Exploitation

NONE

PoC

NONE

Patch

AVAILABLE

Momentum

STABLE

Are you affected?

If you run products in this scope, you should treat this CVE as relevant to your environment.

  • linux_kernel

Threat summary

  • 6 mentions across 4 observed days
  • Momentum state: stable

What's happening

  • General: 6 classified signals
  • Peaked 3d ago at 2 mentions (2026-05-14); latest day: 1
  • 6 total mentions across 4 days

Affected systems

Vendors
linux
Products
linux_kernel

Deep dive

Activity timeline6 mentions / 4d
01122Mentions · 2026-05-14: 2Mentions · 2026-05-15: 1Mentions · 2026-05-22: 2Mentions · 2026-06-01: 105-1405-1505-2206-01
Signal classification1 categories
General
6100.0%
Classification over time
DateTotalLabels
2026-05-142
General2
2026-05-151
General1
2026-05-222
General2
2026-06-011
General1
Full discourse6 posts
  • hsn今天吃什么@hsn8086k
    General

    2026 Linux 重置密码教程大全 - Dirty Cow (CVE-2016-5195) - Dirty Pipe (CVE-2022-0847) - io_uring UAF (CVE-2022-2602) - Copy Fail (CVE-2026-31431) - io_uring ZCRX freelist (CVE-2026-43121) - Dirty Frag (CVE-2026-43284 CVE-2026-43500) - Fragnesia (CVE-2026-46300)

    Post summary

    The text is a simple list of Linux CVEs and a tutorial title, with no additional information on exploits, patches, or technical details.

    17193111.1K50579.9K
    2.3K followersView on X
  • hsn今天吃什么@hsn8086k
    General

    Linux 重置密码大全 - Dirty Cow (CVE-2016-5195) - Dirty Pipe (CVE-2022-0847) - io_uring UAF (CVE-2022-2602) - Copy Fail (CVE-2026-31431) - io_uring ZCRX freelist (CVE-2026-43121) - Dirty Frag (CVE-2026-43284 CVE-2026-43500) - Fragnesia (CVE-2026-46300) -PinTheft (CVE-2026-43494)

    Post summary

    The text simply lists several Linux CVEs related to password reset methods without providing additional context, technical details, or actionable information.

    43118972036546.3K
    2.3K followersView on X
  • Het Mehta@hetmehtaa
    General

    Them: Linux is most secure OS Me: Yes - Dirty Cow (CVE-2016-5195) - Dirty Pipe (CVE-2022-0847) - io_uring UAF (CVE-2022-2602) - Copy Fail (CVE-2026-31431) - io_uring ZCRX freelist (CVE-2026-43121) - Dirty Frag (CVE-2026-43284 CVE-2026-43500) - Fragnesia (CVE-2026-46300)

    Post summary

    The content merely enumerates a set of Linux kernel CVEs without offering any proof‑of‑concepts, exploit details, active‐exploitation evidence, or mitigation guidance.

    566618598272159.8K
    42.2K followersView on X
  • 好奇猫a@acnekot
    General

    2026 Linux 重置密码教程大全 - Dirty Cow (CVE-2016-5195) - Dirty Pipe (CVE-2022-0847) - io_uring UAF (CVE-2022-2602) - Copy Fail (CVE-2026-31431) - io_uring ZCRX freelist (CVE-2026-43121) - Dirty Frag (CVE-2026-43284 CVE-2026-43500) - Fragnesia (CVE-2026-46300)

    Post summary

    The text simply lists a series of Linux CVEs as part of a tutorial title, providing no explicit PoC, exploits, technical details, patch information, or evidence of active exploitation.

    00040351
    2.4K followersView on X
  • Luis Lescano@luadoles
    General

    - Dirty Cow (CVE-2016-5195) - Dirty Pipe (CVE-2022-0847) - io_uring UAF (CVE-2022-2602) - Copy Fail (CVE-2026-31431) - io_uring ZCRX freelist (CVE-2026-43121) - Dirty Frag (CVE-2026-43284 CVE-2026-43500) - Fragnesia (CVE-2026-46300) -PinTheft (CVE-2026-43494)

    Post summary

    The text enumerates several CVEs without providing any supporting details, mitigations, or evidence of active exploitation.

    10000294
    31 followersView on X
  • みおど@furlingdu
    General

    2026 Linux 重置密码教程大全 - Dirty Cow (CVE-2016-5195) - Dirty Pipe (CVE-2022-0847) - io_uring UAF (CVE-2022-2602) - Copy Fail (CVE-2026-31431) - io_uring ZCRX freelist (CVE-2026-43121) - Dirty Frag (CVE-2026-43284 CVE-2026-43500) - Fragnesia (CVE-2026-46300)

    Post summary

    The entry merely lists a set of Linux CVEs in a tutorial context without providing exploit details, patches, or any deeper technical information.

    00000164
    2.0K followersView on X
CPE platform detail1 entries

1 of 1 entries

PartVendorProductVersionTarget SWTarget HW
OSlinuxlinux_kernel---

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