High

Linux kernel eventpoll use-after-free in ep_free

IdentifiersCVE-2026-43074CWE-416

CVE-2026-43074 is a use-after-free vulnerability in the Linux kernel eventpoll subsystem. According to the provided content, in certain concurrent execution scenarios, ep_free() in eventpoll.c can free the epi->ep struct eventpoll object with kfree() while another thread is still using that structure. The fix is to defer freeing of the struct eventpoll object until an RCU grace period has elapsed, preventing concurrent readers from accessing freed memory.

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ANALYST BRIEF

Impact, mitigation & remediation

What it means. What to do now. Patch path, mitigations, and the assume-compromise checklist.

Impact

What an attacker gets, and what they’ve been doing with it.

Successful exploitation can trigger a kernel-space use-after-free condition, leading to memory corruption, kernel instability, crashes, or denial of service. As with other kernel UAF flaws, impact may extend beyond DoS to potential privilege escalation or arbitrary code execution in kernel context if an attacker can reliably shape heap state and win the race, although the provided content does not confirm demonstrated exploitation.

Mitigation

If you can’t patch tonight, do this now.

If immediate patching is not possible, reduce exposure by limiting untrusted local code execution on affected systems, since exploitation depends on triggering concurrent eventpoll activity in kernel context. Standard kernel hardening and least-privilege controls may reduce practical exploitability, but no complete mitigation is provided in the supplied content short of applying the fix.

Remediation

Patch, then assume compromise.

Upgrade to a Linux kernel release that includes the fix for CVE-2026-43074. The remediation described in the provided content is to modify the eventpoll teardown path so that freeing of struct eventpoll is deferred via an RCU callback rather than immediate kfree() in ep_free(). Apply the relevant upstream or vendor backport for this patch, including LTS updates where applicable.

PUBLIC EXPLOITS

Exploits

No public exploits tracked yet. Mallory keeps watching.

VALID 0 / 0 TOTALView more in app

No public exploit code observed for this vulnerability.

EXPOSURE SURFACE

Affected products & vendors

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VendorProductType

LinuxLinux Kerneloperating_system

Vendor-confirmed product mapping. Mallory continuously reconciles this list against your asset inventory.

ACTIVITY FEED

Recent activity

1 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.

1 SOURCESView more in app

google security research pull requestsNews

May 11, 2026

Add kernelCTF CVE-2026-43074_lts by 2045castor · Pull Request #380 · google/security-research · GitHub

Unknown

What this page doesn’t show

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Exposure mapping

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Threat actor evidence

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Associated malware

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Detection signatures

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Vendor-by-vendor mapping

Cross-references every affected SKU, including bundled OEM variants.

Social activity