VulnerabilityPublished 25 Jul 2026

CVE-2026-64452: Linux kernel · 6lowpan: fix NHC entry use-after-free on error path

Source GCVE Database

Authoritative record:CVE-2026-64452· High 7.1

Not known to be exploited · CVSS 7.1 High · fixed in cc27aea4d454abfb385ee2c9499c78b96db9b728 : patch Linux kernel soon.

Data as of 26 Oct 2026, 13:47 UTC

CVSS 3.1 base score

7.1High

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

EPSS: 0.2% chance of exploitation in 30 days – higher than 12% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in cc27aea4d454abfb385ee2c9499c78b96db9b728, b713aa0cc344f10f7a9928a230b5f5e780d04078, a8e3a94711134e898c6021a6b77374efa91b3639 +5

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

Attack Vector: Adjacent
Attack Complexity: High
Privileges Required: None
User Interaction: Required
Scope: Unchanged
Confidentiality: High
Integrity: High
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: High: A successful attack depends on conditions beyond the attacker's control. That is, a successful attack cannot be accomplished at will, but requires the attacker to invest in some measurable amount of effort in preparation or execution against the vulnerable component before a successful attack can be expected. For example, a successful attack may require an attacker to: gather knowledge about the environment in which the vulnerable target/component exists; prepare the target environment to improve exploit reliability; or inject themselves into the logical network path between the target and the resource requested by the victim in order to read and/or modify network communications (e.g., a man in the middle attack).
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: Required: Successful exploitation of this vulnerability requires a user to take some action before the vulnerability can be exploited.
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 25 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-c2hf-fh99-25vq

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected ≥ 92aa7c65d295f3cbb96904afe335f683e55584b8, < cc27aea4d454abfb385ee2c9499c78b96db9b728	Fixed in cc27aea4d454abfb385ee2c9499c78b96db9b728
LinuxLinux	Affected ≥ 92aa7c65d295f3cbb96904afe335f683e55584b8, < b713aa0cc344f10f7a9928a230b5f5e780d04078	Fixed in b713aa0cc344f10f7a9928a230b5f5e780d04078
LinuxLinux	Affected ≥ 92aa7c65d295f3cbb96904afe335f683e55584b8, < a8e3a94711134e898c6021a6b77374efa91b3639	Fixed in a8e3a94711134e898c6021a6b77374efa91b3639
LinuxLinux	Affected ≥ 92aa7c65d295f3cbb96904afe335f683e55584b8, < 1720db928e5a58ca7d75ac1d514c3b73fd7061a7	Fixed in 1720db928e5a58ca7d75ac1d514c3b73fd7061a7
LinuxLinux	Affected ≥ 92aa7c65d295f3cbb96904afe335f683e55584b8, < 593b78bb3c7ef0c6e9ae6fdf5afa80a5f7573168	Fixed in 593b78bb3c7ef0c6e9ae6fdf5afa80a5f7573168
LinuxLinux	Affected ≥ 92aa7c65d295f3cbb96904afe335f683e55584b8, < 80b5c8779acee0550845394fb3e5176a398aa24c	Fixed in 80b5c8779acee0550845394fb3e5176a398aa24c

AI-suggested

A fix is available and has been applied in the Linux kernel to address this use-after-free vulnerability by reordering operations to maintain locking during descriptor name access. Users should update to the fixed kernel version once available. Patch status is not explicitly confirmed in the provided data; check the official Linux kernel advisories or vendor updates for the exact fixed versions and apply them promptly.

Description

In the Linux kernel, the following vulnerability has been resolved: 6lowpan: fix NHC entry use-after-free on error path lowpan_nhc_do_uncompression() looks up an NHC descriptor while holding lowpan_nhc_lock. If the descriptor has no uncompress callback, the error path drops the lock before printing nhc->name. lowpan_nhc_del() removes descriptors under the same lock and then relies on synchronize_net() before the owning module can be unloaded. That only waits for net RX RCU readers. lowpan_header_decompress() is also exported and can be reached from callers that are not necessarily covered by the net core RX critical section, for example the Bluetooth 6LoWPAN L2CAP receive path. This leaves a race where one task drops lowpan_nhc_lock in the error path, another task unregisters and frees the matching descriptor after synchronize_net() returns, and the first task then dereferences nhc->name for the warning. With the post-unlock window widened, KASAN reports: BUG: KASAN: slab-use-after-free in lowpan_nhc_do_uncompression+0x1f4/0x220 Read of size 8 lowpan_nhc_do_uncompression lowpan_header_decompress Fix this by printing the warning before dropping lowpan_nhc_lock, so the descriptor name is read while unregister is still excluded. The malformed packet is still rejected with -ENOTSUPP.

Impact

This vulnerability can cause a use-after-free memory access in the kernel, which may lead to kernel crashes or undefined behavior. There is no indication of remote code execution or privilege escalation in the provided data. The malformed packet causing the error is rejected, limiting impact to denial of service or system instability.

Summary

The Linux kernel's 6LoWPAN code had a use-after-free vulnerability (CVE-2026-64452) in the lowpan_nhc_do_uncompression() function. The function looks up an NHC descriptor while holding a lock, but on an error path, it releases the lock before printing the descriptor's name. Meanwhile, another task could unregister and free the descriptor after synchronize_net() returns, leading to a race condition where the first task dereferences freed memory. The vulnerability was fixed by changing the code to print the warning while still holding the lock, preventing use-after-free access.

References

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