CyberSecBulletin
CVE-2026-46138NVD status: Undergoing Analysis

Linux: Out-of-bounds Read

Published Updated By the CyberSecBulletin desk

CVE-2026-46138 is a high-severity out-of-bounds read vulnerability in Linux, with a CVSS 3.1 base score of 8.1 out of 10. It can be exploited from the same local network by an unauthenticated attacker, without any action from a user. The record lists versions 6cb7f67bc28da787499291a562d49a084d9c90cd, 22559ad7654f61727fc270ee4893da9f4b70cf17, 77981a507aa0fc001dc37f0dd6631dd2042fed17 as the first without the flaw, so updating Linux to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.28% chance of exploitation within 30 days, which is low compared with other CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Update Linux to 6cb7f67bc28da787499291a562d49a084d9c90cd or 22559ad7654f61727fc270ee4893da9f4b70cf17 or 77981a507aa0fc001dc37f0dd6631dd2042fed17 or 665da0baaf0396f9ed3c86ccb3955dcd0b73e774, whichever matches your release line, or a later version.
  2. Update Linux Kernel to 6.5 or 6.6.140 or 6.12.88 or 6.18.30, whichever matches your release line, or a later version.

Affected products and versions

VendorProductAffected versionsFixed in
LinuxLinuxa0bfde167b506423111ddb8cd71930497a40fc54 up to, but not including, 6cb7f67bc28da787499291a562d49a084d9c90cd; a0bfde167b506423111ddb8cd71930497a40fc54 up to, but not including, 22559ad7654f61727fc270ee4893da9f4b70cf17; a0bfde167b506423111ddb8cd71930497a40fc54 up to, but not including, 77981a507aa0fc001dc37f0dd6631dd2042fed17; a0bfde167b506423111ddb8cd71930497a40fc54 up to, but not including, 665da0baaf0396f9ed3c86ccb3955dcd0b73e774; a0bfde167b506423111ddb8cd71930497a40fc54 up to, but not including, 5ddb8014261137cadaf83ab5617a588d80a22586; b475c1109251e30ec21fb574d72a1c71a4ab0039; 2ccde10127447c1a5caad8469fede945bdb62fdf; 6.4.16 up to, but not including, 6.5; and 2 more ranges6cb7f67bc28da787499291a562d49a084d9c90cd, 22559ad7654f61727fc270ee4893da9f4b70cf17, 77981a507aa0fc001dc37f0dd6631dd2042fed17, 665da0baaf0396f9ed3c86ccb3955dcd0b73e774, 5ddb8014261137cadaf83ab5617a588d80a22586, 6.5
LinuxLinux Kernel6.4.16 up to, but not including, 6.5; 6.5.3 up to, but not including, 6.6.140; 6.7 up to, but not including, 6.12.88; 6.13 up to, but not including, 6.18.30; 6.19 up to, but not including, 7.0.7; 7.16.5, 6.6.140, 6.12.88, 6.18.30, 7.0.7

Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
AdjacentThe attacker must be on the same local network segment.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Privileges required
NoneNo account or login is needed.
User interaction
NoneNo action by a victim is required.
Scope
UnchangedImpact stays within the vulnerable component.
Confidentiality
HighAll data handled by the component can be read.
Integrity
NoneNothing can be modified.
Availability
HighThe component can be taken down completely.

Vector: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H. Scored by CNA.

Official description

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: hci_event: Fix OOB read and infinite loop in hci_le_create_big_complete_evt hci_le_create_big_complete_evt() iterates over BT_BOUND connections for a BIG handle using a while loop, accessing ev->bis_handle[i++] on each iteration. However, there is no check that i stays within ev->num_bis before the array access. When a controller sends a LE_Create_BIG_Complete event with fewer bis_handle entries than there are BT_BOUND connections for that BIG, or with num_bis=0, the loop reads beyond the valid bis_handle[] flex array into adjacent heap memory. Since the out-of-bounds values typically exceed HCI_CONN_HANDLE_MAX (0x0EFF), hci_conn_set_handle() rejects them and the connection remains in BT_BOUND state. The same connection is then found again by hci_conn_hash_lookup_big_state(), creating an infinite loop with hci_dev_lock held. Fix this by terminating the BIG if in case not all BIS could be setup properly.

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Out-of-bounds Read

The product reads data past the end, or before the beginning, of the intended buffer.

How developers prevent this class of flaw

  • Use a language that provides appropriate memory abstractions.

More Out-of-bounds Read vulnerabilities (CWE-125)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: partial).
  3. Record last changed materially (score, affected products, status or references).

References

Recent Out-of-bounds Read vulnerabilities

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