High

CVE-2026-98253 — RDMA/ucma: Serialize join and leave on copy_to_user failure

In the Linux kernel, the following vulnerability has been resolved: RDMA/ucma: Serialize join and leave on copy_to_user failure rdma_join_multicast() queues RoCE work that later reads the ucma_multicast through event->param.ud.private_data, then list_add()s the CMA multicast at the head of id_priv->mc_list. rdma_leave_multicast() matches only by sockaddr and destroys the first hit. ucma_process_join() used to drop ctx->mutex after a successful join and retake it only if copy_to_user() failed. Two concurrent JOIN_MCAST calls with the same address can therefore insert a second CMA entry before the first thread's leave. leave then cancels the newer work and the older worker still dereferences the ucma_multicast that the first thread frees. Keep ctx->mutex held from rdma_join_multicast() through copy_to_user() and, on -EFAULT, through rdma_leave_multicast() so leave cannot miss this join. Do not leave if join itself failed: that path never published this address on mc_list, and a leave-by-addr would destroy an earlier successful join.

Published Oct 6, 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 0.1% (30-day exploitation probability)+0
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

0.14%

ahead of 3% of scored CVEs · Oct 14, 2026

Affects

Linux

CVSS base

7.8

High · 2 source(s)

Remediation

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

No fix documented by the sources we poll. That does not mean none exists: check the vendor advisory.

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).
No fix documented in the sources: reduce exposure and monitor the vendor advisory.
Search available logs for exploit probes, errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

Vendor	Product	Versions	Status	Source
Linux	Linux	≥ 60d613b39e8d0c9f3b526e9c96445422b4562d76 and < 29b9ed83d8bfab5c6e11fcbf1aa836aa4ae26cb9≥ fe454dc31e84f8c14cb8942fcb61666c9f40745b and < 52172e11bd074ccaded21740ffeb67123f01dd00≥ fe454dc31e84f8c14cb8942fcb61666c9f40745b and < 01e29d0d78a8f66f221625720a04939eef5ec1f6≥ fe454dc31e84f8c14cb8942fcb61666c9f40745b and < ae805d204cf1f15b87d1bf3529b4c649f3519420≥ fe454dc31e84f8c14cb8942fcb61666c9f40745b and < 43c4e24bd10370fc976f6220518049ce71419399≥ fe454dc31e84f8c14cb8942fcb61666c9f40745b and < 01cbdb724c584d7772fd25af2e4dfdf8527ce0d5≥ fe454dc31e84f8c14cb8942fcb61666c9f40745b and < 83610ee5e498fa5bfcb80031d2b959baea276bf6≥ fe454dc31e84f8c14cb8942fcb61666c9f40745b and < 662ade4de9ff5eceb0820a9f8e9fac70ba6a815b and 4 more version a3262b3884dd67b4c5632ce7cdf9cff9d1a575d4≥ 5.10.20 and < 5.10.271≥ 5.11.3 and < 5.12version 5.12	Vulnerable	CVE Program (cve.org) e CISA ADP

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)

EPSS over time FIRST

Oct 13, 2026 → Oct 14, 2026 · 2 reading(s) · max 0.14%

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.

endpoint telemetry (EDR)

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
CVSS changed · 7.8
Oct 13, 2026 · NIST National Vulnerability Database
Source status changed · → Received
Oct 13, 2026 · NIST National Vulnerability Database
Record created in this database
Oct 13, 2026 · NIST National Vulnerability Database
CVE published
Oct 6, 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/43c4e24bd10370fc976f6220518049ce71419399
NIST National Vulnerability Database
git.kernel.org/stable/c/83610ee5e498fa5bfcb80031d2b959baea276bf6
NIST National Vulnerability Database
git.kernel.org/stable/c/01cbdb724c584d7772fd25af2e4dfdf8527ce0d5
NIST National Vulnerability Database
git.kernel.org/stable/c/29b9ed83d8bfab5c6e11fcbf1aa836aa4ae26cb9
NIST National Vulnerability Database
git.kernel.org/stable/c/662ade4de9ff5eceb0820a9f8e9fac70ba6a815b
NIST National Vulnerability Database
git.kernel.org/stable/c/ae805d204cf1f15b87d1bf3529b4c649f3519420
NIST National Vulnerability Database
git.kernel.org/stable/c/01e29d0d78a8f66f221625720a04939eef5ec1f6
NIST National Vulnerability Database
git.kernel.org/stable/c/52172e11bd074ccaded21740ffeb67123f01dd00
NIST National Vulnerability Database

Elsewhere on this site

Linux
every CVE for this vendor

Related CVEs (same products)

Critical CVE-2026-99999 ipv4: validate checksum_start before completing checksum 9h
Unknown CVE-2026-98432 ipv4: free inet_opt and ireq_opt after an RCU grace period 9h
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 fixed version, patch or mitigation documented.
No CISA SSVC assessment.
No CWE classification.
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-2026-98253 is "RDMA/ucma: Serialize join and leave on copy_to_user failure", 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 0.14% 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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