High Memory corruption

CVE-2026-46242 — eventpoll: fix ep_remove struct eventpoll / struct file UAF

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.

Published May 30, 2026 · Updated Oct 13, 2026 · Sources: NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP · CNA: Linux

Low

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

No exploitation signal in the sources consulted so far.

How the score was calculated

EPSS 4.4% (30-day exploitation probability)+14
Technical severity (high)+6

The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

Exploitation

Not confirmed

Not in CISA KEV — an absence of record, not proof it is unexploited.

EPSS FIRST

4.39%

ahead of 91% of scored CVEs · Oct 14, 2026

Affects

Linux

Linux and 1 more

CVSS base

7.8

High · 2 source(s)

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

Documented patch — git.kernel.org (NIST National Vulnerability Database)
Documented patch — git.kernel.org (NIST National Vulnerability Database)
Documented patch — git.kernel.org (NIST National Vulnerability Database)

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

Identify exposed assets running the affected vendor/product/version combinations (Linux Linux, Linux Linux Kernel).
Apply the fixed version or the patch documented under Remediation.
EPSS ahead of 91% of scored CVEs: prioritize it in the patch queue.
Search available logs for exploit probes matching the vulnerability class (memory corruption), errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

Vendor	Product	Versions	Status	Source
Linux	Linux	≥ f2451def095c1743adcfcb0cb5dadc86034e162a and < a10fbbe74e1c743beb1bb312109366667461df8a≥ a1f93804449d13f97dabd4b996817de4bf1ed67a and < 3e1144d2515d28e4312e663ea05eac203101491d≥ 58c9b016e12855286370dfb704c08498edbc857a and < 2de4db145b2992da496fea6c51f9839be678ae24≥ 58c9b016e12855286370dfb704c08498edbc857a and < 9324de74a3a59b9fde9b62ee45ebaa71458ba2e5≥ 58c9b016e12855286370dfb704c08498edbc857a and < ef4ca02e95363e78977ca04340d44fe3b4b2b81f≥ 58c9b016e12855286370dfb704c08498edbc857a and < ced39b6a8062bac5c18a1c3df85634107eb8664a≥ 58c9b016e12855286370dfb704c08498edbc857a and < a6dc643c69311677c574a0f17a3f4d66a5f3744b≥ 5.15.209 and < 5.15.222 and 2 more ≥ 6.1.175 and < 6.1.178version 6.4	Vulnerable	CVE Program (cve.org) e CISA ADP
Linux	Linux Kernel	≥ 5.15.209 and < 5.16≥ 6.1.175 and < 6.2≥ 6.4 and < 6.18.33≥ 6.19 and < 7.0.10	Vulnerable	NIST National Vulnerability Database

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Attack vector

Local

Attack complexity

Low

Privileges required

Low

User interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Every base score collected

Sources score independently and may disagree; each row says who scored it and under which version.

Score	Version	Severity	Expl.	Impact	Scored by
7.8	CVSS 3.1	High	1.8	5.9	416baaa9-dc9f-4396-8d5f-8c081fb06d67 via NIST National Vulnerability Database
7.8	CVSS 3.1	High	—	—	Linux via CVE Program (cve.org) e CISA ADP

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H (score shown at the top: 416baaa9-dc9f-4396-8d5f-8c081fb06d67)

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-416 · Use After Free

Other CVEs with this weakness →

EPSS over time FIRST

Oct 13, 2026 → Oct 14, 2026 · 2 reading(s) · max 4.39%

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

Local/physical vector: focus on endpoint telemetry (EDR) from affected hosts.
Correlate service crashes/restarts with inbound traffic; repeated crashes may indicate attempts.

endpoint telemetry (EDR)crash dumps

Timeline

What happened to this CVE, newest first.

2026
Affected products added · linux/linux
Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
Record published
Oct 13, 2026
Fix documented
Oct 13, 2026 · NIST National Vulnerability Database
CVSS changed · 7.8
Oct 13, 2026 · NIST National Vulnerability Database
Source status changed · → Modified
Oct 13, 2026 · NIST National Vulnerability Database
Record created in this database
Oct 13, 2026 · NIST National Vulnerability Database
CVE published
May 30, 2026 · Linux

Source activity

Repeated readings are counted rather than listed.

1× Official description updated · Oct 13, 2026 – Oct 13, 2026

References

8 on the record

git.kernel.org/stable/c/ef4ca02e95363e78977ca04340d44fe3b4b2b81f
Patch, NIST National Vulnerability Database
git.kernel.org/stable/c/a6dc643c69311677c574a0f17a3f4d66a5f3744b
Patch, NIST National Vulnerability Database
git.kernel.org/stable/c/ced39b6a8062bac5c18a1c3df85634107eb8664a
Patch, NIST National Vulnerability Database
git.kernel.org/stable/c/2de4db145b2992da496fea6c51f9839be678ae24
NIST National Vulnerability Database
git.kernel.org/stable/c/3e1144d2515d28e4312e663ea05eac203101491d
NIST National Vulnerability Database
git.kernel.org/stable/c/a10fbbe74e1c743beb1bb312109366667461df8a
NIST National Vulnerability Database
www.openwall.com/lists/oss-security/2026/07/08/14
NIST National Vulnerability Database
git.kernel.org/stable/c/9324de74a3a59b9fde9b62ee45ebaa71458ba2e5
NIST National Vulnerability Database

Elsewhere on this site

Linux
every CVE for this vendor

Memory corruption
same class

CWE-416
other pages naming this weakness

Related CVEs (same products)

Critical CVE-2026-99999 ipv4: validate checksum_start before completing checksum 12h
Unknown CVE-2026-98432 ipv4: free inet_opt and ireq_opt after an RCU grace period 12h
Unknown CVE-2026-98424 wifi: cfg80211: undo netns switch if renaming the wiphy fails 1d
Unknown CVE-2026-98425 wifi: mac80211: don't warn when an IBSS has no channel to scan 1d
Unknown CVE-2026-98426 wifi: mwifiex: fix IRQ leak using wrong index in MSI-X error path 1d
Unknown CVE-2026-98427 net/sched: codel: bound the dropping loop per dequeue call 1d

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

No CISA SSVC assessment.
No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2026-46242 is "eventpoll: fix ep_remove struct eventpoll / struct file UAF", rated High. It affects Linux (Linux); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 7.8 describes technical severity. EPSS 4.39% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

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