VulnerabilityPublished 27 Jul 2026Updated 30 Jul 2026

CVE-2026-64541: Linux kernel · net/smc: fix UAF in smc_cdc_rx_handler() by pinning the socket

Source GCVE Database

Authoritative record:CVE-2026-64541· Critical 9.8

Not known to be exploited · CVSS 9.8 Critical · fixed in ce5aa8084329351086894aa34d77e40301d5bd3d : patch Linux kernel as a priority.

Data as of 26 Oct 2026, 14:05 UTC

CVSS 3.1 base score

9.8Critical

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.5% chance of exploitation in 30 days – higher than 46% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in ce5aa8084329351086894aa34d77e40301d5bd3d, 8145b432136285e01091815b48ceb2dae261f262, 1951bffbc6493ec34cff3956b29d4bc6606904a6 +5

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

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: None
Scope: Unchanged
Confidentiality: High
Integrity: High
Availability: High

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: High: There is total loss of confidentiality, resulting in all resources within the impacted component being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact.
Integrity: High: There is a total loss of integrity, or a complete loss of protection. For example, the attacker is able to modify any/all files protected by the impacted component. Alternatively, only some files can be modified, but malicious modification would present a direct, serious consequence to the impacted component.
Availability: High: There is total loss of availability, resulting in the attacker being able to fully deny access to resources in the impacted component; this loss is either sustained (while the attacker continues to deliver the attack) or persistent (the condition persists even after the attack has completed). Alternatively, the attacker has the ability to deny some availability, but the loss of availability presents a direct, serious consequence to the impacted component (e.g., the attacker cannot disrupt existing connections, but can prevent new connections; the attacker can repeatedly exploit a vulnerability that, in each instance of a successful attack, leaks a only small amount of memory, but after repeated exploitation causes a service to become completely unavailable).

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 27 Jul 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

ghsa-wjv3-3r54-x298

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected ≥ d7b0e37c1ac152905b18a5b9506179091a35b0b6, < ce5aa8084329351086894aa34d77e40301d5bd3d	Fixed in ce5aa8084329351086894aa34d77e40301d5bd3d
LinuxLinux	Affected ≥ d7b0e37c1ac152905b18a5b9506179091a35b0b6, < 8145b432136285e01091815b48ceb2dae261f262	Fixed in 8145b432136285e01091815b48ceb2dae261f262
LinuxLinux	Affected ≥ d7b0e37c1ac152905b18a5b9506179091a35b0b6, < 1951bffbc6493ec34cff3956b29d4bc6606904a6	Fixed in 1951bffbc6493ec34cff3956b29d4bc6606904a6
LinuxLinux	Affected ≥ d7b0e37c1ac152905b18a5b9506179091a35b0b6, < 647b19e5cc145a2f1f685ae8ff3805a17356888c	Fixed in 647b19e5cc145a2f1f685ae8ff3805a17356888c
LinuxLinux	Affected ≥ d7b0e37c1ac152905b18a5b9506179091a35b0b6, < 472e9d7c0d5b03be3ff91ff941f57da822b031bc	Fixed in 472e9d7c0d5b03be3ff91ff941f57da822b031bc
LinuxLinux	Affected ≥ d7b0e37c1ac152905b18a5b9506179091a35b0b6, < 9d160b35cc34a2ba8229d07651468a7848325135	Fixed in 9d160b35cc34a2ba8229d07651468a7848325135

AI-suggested

A fix is available and has been applied in the Linux kernel to address this use-after-free vulnerability by modifying the socket reference handling in smc_cdc_rx_handler(). Users and administrators should update to the latest Linux kernel version containing this fix. Since this is not a cloud service, manual patching is required. Patch status is not explicitly confirmed in the provided data; therefore, verify the vendor advisory or Linux kernel changelogs for the exact fixed versions and apply updates accordingly.

Description

A use-after-free (UAF) vulnerability was identified and resolved in the Linux kernel's SMC-R subsystem within the smc_cdc_rx_handler() function. The issue arises because the socket reference is not properly pinned while the connection lock is released, allowing a concurrent socket release and free operation to occur. This leads to dereferencing freed memory, which can cause kernel panics and potentially allow an attacker to compromise confidentiality, integrity, and availability. The vulnerability affects only the SMC-R protocol implementation and not SMC-D. The fix involves taking the socket reference while holding the connection lock to prevent concurrent frees during handler execution.

Impact

Successful exploitation of this vulnerability can lead to a kernel panic, causing denial of service. The CVSS vector indicates network attack vector, low attack complexity, no privileges or user interaction required, and impacts confidentiality, integrity, and availability at a high level. This means an unauthenticated remote attacker could potentially cause system crashes and compromise system security through this flaw in the SMC-R protocol handling.

Summary

The Linux kernel contained a use-after-free vulnerability in the smc_cdc_rx_handler() function of the SMC-R protocol implementation. The handler looked up a connection under a lock, then released the lock before referencing the connection and socket, which could be freed concurrently by a close operation. This caused sock_hold() to operate on freed memory, leading to kernel panics. The vulnerability was fixed by ensuring the socket reference is taken while still holding the connection lock, preventing the reference from being dropped concurrently and avoiding use-after-free conditions.

References

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