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CVE-2026-46242

eventpoll: fix ep_remove struct eventpoll / struct file UAF

No known exploitation. EPSS puts it in the 6th percentile. Fixed versions are out.

CVSS 3.17.8HighEPSS percentile6th0.2% chance in 30 daysCISA KEVNot listedNo confirmed exploitation
No public exploit knownFix1 product4 fixed builds listed below

Published Updated Sources: CVE.org, NVD

NVD CVE.org

What to do

Find your product and version, then upgrade to the build on the right.

  • LinuxAffected: ≥ f2451def095c1743adcfcb0cb5dadc86034e162a, < a10fbbe74e1c743beb1bb312109366667461df8aUpgrade to: a10fbbe74e1c743beb1bb312109366667461df8aAffected: ≥ a1f93804449d13f97dabd4b996817de4bf1ed67a, < 3e1144d2515d28e4312e663ea05eac203101491dUpgrade to: 3e1144d2515d28e4312e663ea05eac203101491dAffected: ≥ 58c9b016e12855286370dfb704c08498edbc857a, < 2de4db145b2992da496fea6c51f9839be678ae24Upgrade to: 2de4db145b2992da496fea6c51f9839be678ae24Affected: ≥ 58c9b016e12855286370dfb704c08498edbc857a, < 9324de74a3a59b9fde9b62ee45ebaa71458ba2e5Upgrade to: 9324de74a3a59b9fde9b62ee45ebaa71458ba2e5 + 5 more branchesStated by: CVE record

Versions as the sources state them. Full version matrix after sign-in

Check it yourselfA free OpenVAS check exists for this CVE. Run it against your hosts.Is your organisation exposed?Request an assessment to establish which checks fit your systems.

Coverage timeline

4 publishers

  1. Proof-of-concept published

    ·Хакер (xakep.ru) summary

  2. Advisory coverage

    ·Check Point Research summary

  3. Technical analysis published

    ·The Hacker News summary

Sourced from public security reporting — each date is when it was published, not when it happened. 4 further articles named this CVE in wider roundups without reporting it as a distinct event.

What it is

From the CVE record

In the Linux kernel, the following vulnerability has been resolved: eventpoll: fix ep_remove struct eventpoll / struct file UAF ep_remove() (via ep_remove_file()) cleared file->f_ep under file->f_lock but then kept using @file inside the critical section (is_file_epoll(), hlist_del_rcu() through the head, spin_unlock). A concurrent __fput() taking the eventpoll_release() fastpath in that window observed the transient NULL, skipped eventpoll_release_file() and ran to f_op->release / file_free(). For the epoll-watches-epoll case, f_op->release is ep_eventpoll_release() -> ep_clear_and_put() -> ep_free(), which kfree()s the watched struct eventpoll. Its embedded ->refs hlist_head is exactly where epi->fllink.pprev points, so the subsequent hlist_del_rcu()'s "*pprev = next" scribbles into freed kmalloc-192 memory. In addition, struct file is SLAB_TYPESAFE_BY_RCU, so the slot backing @file could be recycled by alloc_empty_file() -- reinitializing f_lock and f_ep -- while ep_remove() is still nominally inside that lock. The upshot is an attacker-controllable kmem_cache_free() against the wrong slab cache. Pin @file via epi_fget() at the top of ep_remove() and gate the critical section on the pin succeeding. With the pin held @file cannot reach refcount zero, which holds __fput() off and transitively keeps the watched struct eventpoll alive across the hlist_del_rcu() and the f_lock use, closing both UAFs. If the pin fails @file has already reached refcount zero and its __fput() is in flight. Because we bailed before clearing f_ep, that path takes the eventpoll_release() slow path into eventpoll_release_file() and blocks on ep->mtx until the waiter side's ep_clear_and_put() drops it. The bailed epi's share of ep->refcount stays intact, so the trailing ep_refcount_dec_and_test() in ep_clear_and_put() cannot free the eventpoll out from under eventpoll_release_file(); the orphaned epi is then cleaned up there. A successful pin also proves we are not racing eventpoll_release_file() on this epi, so drop the now-redundant re-check of epi->dying under f_lock. The cheap lockless READ_ONCE(epi->dying) fast-path bailout stays.

In plain language

No plain-language summary for this CVE yet.

Exploitation

Where each signal puts this CVE on the scale from published to confirmed exploited.

EPSS6th
CISA KEV

Not in the catalog. CISA has not confirmed exploitation.

Public exploits

No public exploit or proof of concept found in the sources we track.

EPSS

0.2% chance of exploitation activity in the next 30 days, which ranks it in the 6th percentile of scored CVEs.

Exploit Prediction Scoring System, FIRST.org. A probability, not a confirmation.

Lifecycle

14 events over 126 days, from the signal feeds we watch.

  1. Patch availablerecord updated
  2. Patch availablerecord updated
  3. Patch availablerecord updated
  4. Patch availablerecord updated
  5. Patch availablerecord updated
  6. OpenVAS check added

Affected products

And 1 more affected product. See all after sign-in

Technical detail

CVSS 3.1 vector

Open in the CVSS calculator

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Scored 7.8 by NVD.

How it is reached

  • Attack Vector LocalRequires local access to the vulnerable system (e.g. local login, malicious file)
  • Attack Complexity LowNo special conditions — the attack can be reliably reproduced
  • Privileges Required LowRequires basic user-level privileges
  • User Interaction NoneNo user interaction needed — fully automated exploitation

Scope

  • Scope UnchangedImpact is limited to the vulnerable component itself

Impact if exploited

  • Confidentiality HighTotal information disclosure — all data in the component is compromised
  • Integrity HighTotal loss of integrity — attacker can modify any data in the component
  • Availability HighTotal denial of service — the component is completely unavailable

Weaknesses

ATT&CK techniques

Mapped from the weaknesses above (CWE to ATT&CK), not observed in attacks.

Sources

References in the record

And 5 more references. See all after sign-in

In the news

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