VulnerabilityPublished 27 Jul 2026Updated 30 Jul 2026

CVE-2026-64540: Linux kernel · usbnet: gl620a: fix out-of-bounds read in genelink_rx_fixup()

Source GCVE Database

Authoritative record:CVE-2026-64540· High 8.1

Not known to be exploited · CVSS 8.1 High · fixed in 4359376e6238d89977a35086e47ca3b07f43e850 : patch Linux kernel soon.

Data as of 26 Oct 2026, 17:16 UTC

CVSS 3.1 base score

8.1High

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

EPSS: 0.2% chance of exploitation in 30 days – higher than 19% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 4359376e6238d89977a35086e47ca3b07f43e850, 0575599e451aff3c5329922562374a2cab25fc51, 573418f7ea8f859a841417eb4b915594094fd967 +5

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

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

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

Attack Vector: Adjacent: The vulnerable component is bound to the network stack, but the attack is limited at the protocol level to a logically adjacent topology. This can mean an attack must be launched from the same shared physical (e.g., Bluetooth or IEEE 802.11) or logical (e.g., local IP subnet) network, or from within a secure or otherwise limited administrative domain (e.g., MPLS, secure VPN to an administrative network zone).
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: None: There is no loss of integrity within 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-rwwq-q965-ghfj

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected ≥ 47ee3051c856cc2aa95d35d577a8cb37279d540f, < 4359376e6238d89977a35086e47ca3b07f43e850	Fixed in 4359376e6238d89977a35086e47ca3b07f43e850
LinuxLinux	Affected ≥ 47ee3051c856cc2aa95d35d577a8cb37279d540f, < 0575599e451aff3c5329922562374a2cab25fc51	Fixed in 0575599e451aff3c5329922562374a2cab25fc51
LinuxLinux	Affected ≥ 47ee3051c856cc2aa95d35d577a8cb37279d540f, < 573418f7ea8f859a841417eb4b915594094fd967	Fixed in 573418f7ea8f859a841417eb4b915594094fd967
LinuxLinux	Affected ≥ 47ee3051c856cc2aa95d35d577a8cb37279d540f, < 8624e179fa3ce23c2fbd1a198ce30764b73f054a	Fixed in 8624e179fa3ce23c2fbd1a198ce30764b73f054a
LinuxLinux	Affected ≥ 47ee3051c856cc2aa95d35d577a8cb37279d540f, < 255d03551f94c7bdd86c7d9181a70b21917d829f	Fixed in 255d03551f94c7bdd86c7d9181a70b21917d829f
LinuxLinux	Affected ≥ 47ee3051c856cc2aa95d35d577a8cb37279d540f, < 8ff7f2a6da4fccaa5cc9be7251a24e71e29fbd1a	Fixed in 8ff7f2a6da4fccaa5cc9be7251a24e71e29fbd1a

AI-suggested

A fix has been implemented in the Linux kernel to verify packet lengths before copying data in the genelink_rx_fixup() function, preventing out-of-bounds reads. Users should apply the official kernel updates that include this patch. Since this is a kernel-level vulnerability, updating to a patched kernel version is the recommended remediation. Patch status is not explicitly stated here; check the vendor or Linux kernel advisory for the exact fixed version and update accordingly.

Description

A vulnerability in the Linux kernel's usbnet driver for the GeneLink GL620A device allows an out-of-bounds read in the genelink_rx_fixup() function. This occurs because the function uses device-supplied packet lengths without verifying they fit within the actual received data buffer, potentially leaking kernel heap memory. The flaw can be triggered by a malicious USB device without requiring privileges. A fix has been implemented to verify packet lengths before copying data, preventing out-of-bounds reads.

Impact

An attacker controlling a malicious GeneLink GL620A USB device can cause the Linux kernel to perform an out-of-bounds read of kernel heap memory, potentially leaking sensitive kernel information. This occurs without requiring any privileges and can be triggered as soon as the network interface is up. The vulnerability does not allow code execution or privilege escalation directly but can aid in information disclosure and further attacks. The kernel's memory safety is compromised due to this flaw.

References

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