VulnerabilityPublished 1 May 2026Updated 30 Oct 2026

CVE-2026-31771: Linux kernel · Out-of-bounds Read

Source GCVE Database

Authoritative record:CVE-2026-31771· High 8.1

Not known to be exploited · CVSS 8.1 High · fixed in fbea63d0d301edd4a42f4390b49b8519d78b802d : patch Linux kernel soon.

Data as of 30 Oct 2026, 16:33 UTC

CVSS 3.1 base score

8.1High

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

Thin evidence

One scorer or none

CVSS scores by source
CNA (Linux)	CVSS 3.1	8.1

Patch: Available – fixed in fbea63d0d301edd4a42f4390b49b8519d78b802d, dbc8b8d33c9e19e17e8b8b1361bbb46e2983f5f2, ac7889b0fe441e4ef892c40b1d002e91f93fa4ae +3

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 1 May 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: 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 30 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.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), 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-pqp4-p68v-9xfr

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected ≥ 2f20216c1d6fe17c1a224f658be0dc6fab2269c7, < fbea63d0d301edd4a42f4390b49b8519d78b802d	Fixed in fbea63d0d301edd4a42f4390b49b8519d78b802d
LinuxLinux	Affected ≥ 2f20216c1d6fe17c1a224f658be0dc6fab2269c7, < dbc8b8d33c9e19e17e8b8b1361bbb46e2983f5f2	Fixed in dbc8b8d33c9e19e17e8b8b1361bbb46e2983f5f2
LinuxLinux	Affected ≥ 2f20216c1d6fe17c1a224f658be0dc6fab2269c7, < ac7889b0fe441e4ef892c40b1d002e91f93fa4ae	Fixed in ac7889b0fe441e4ef892c40b1d002e91f93fa4ae
LinuxLinux	Affected ≥ 2f20216c1d6fe17c1a224f658be0dc6fab2269c7, < 86c8d07a64d553c41e213b52650020010f9ef23e	Fixed in 86c8d07a64d553c41e213b52650020010f9ef23e
LinuxLinux	Affected ≥ 2f20216c1d6fe17c1a224f658be0dc6fab2269c7, < 2b2bf47cd75518c36fa2d41380e4a40641cc89cd	Fixed in 2b2bf47cd75518c36fa2d41380e4a40641cc89cd
LinuxLinux	Affected ≥ 2f20216c1d6fe17c1a224f658be0dc6fab2269c7, < 1e4b738dd0d0f7b237686167706badad9d30649c	Fixed in 1e4b738dd0d0f7b237686167706badad9d30649c

Description

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: hci_event: move wake reason storage into validated event handlers hci_store_wake_reason() is called from hci_event_packet() immediately after stripping the HCI event header but before hci_event_func() enforces the per-event minimum payload length from hci_ev_table. This means a short HCI event frame can reach bacpy() before any bounds check runs. Rather than duplicating skb parsing and per-event length checks inside hci_store_wake_reason(), move wake-address storage into the individual event handlers after their existing event-length validation has succeeded. Convert hci_store_wake_reason() into a small helper that only stores an already-validated bdaddr while the caller holds hci_dev_lock(). Use the same helper after hci_event_func() with a NULL address to preserve the existing unexpected-wake fallback semantics when no validated event handler records a wake address. Annotate the helper with __must_hold(&hdev->lock) and add lockdep_assert_held(&hdev->lock) so future call paths keep the lock contract explicit. Call the helper from hci_conn_request_evt(), hci_conn_complete_evt(), hci_sync_conn_complete_evt(), le_conn_complete_evt(), hci_le_adv_report_evt(), hci_le_ext_adv_report_evt(), hci_le_direct_adv_report_evt(), hci_le_pa_sync_established_evt(), and hci_le_past_received_evt().

CWE-125Out-of-bounds Read (opens in a new tab)
Base weaknessCWE Top 25 (2025): #8
The product reads data past the end, or before the beginning, of the intended buffer.
Implementation · Input Validation
Assume all input is malicious. Use an "accept known good" input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does.
Architecture and Design · Language Selection
Use a language that provides appropriate memory abstractions.
OWASP Cheat Sheets
XML Security (opens in a new tab)
Mass Assignment (opens in a new tab)
OWASP ASVS 4.0.3
V13.3.1 (opens in a new tab)
V5.1.4 (opens in a new tab)
V5.1.3 (opens in a new tab)
Attack patterns
Overread Buffers (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

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Exploitation evidence

What to do

Affected software

Description

WeaknessesCWE-125

Technical details

References

Community reviews

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