CyberSecBulletin
CVE-2026-43070NVD status: Analyzed

Linux: Out-of-bounds Read

Published Updated By the CyberSecBulletin desk

CVE-2026-43070 is a high-severity out-of-bounds read vulnerability in Linux, with a CVSS 3.1 base score of 7.8 out of 10. It can be exploited with local access to the system by an attacker with a low-privileged account, without any action from a user. The record lists versions a17443af874229408ce6b78e2c8a2b5adeb4b7d8, 0d15c3611a2cc5d08993545d4032055ae10ae2c1, a3125bc01884431d30d731461634c8295b6f0529 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 0.12% 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 a17443af874229408ce6b78e2c8a2b5adeb4b7d8 or 0d15c3611a2cc5d08993545d4032055ae10ae2c1 or a3125bc01884431d30d731461634c8295b6f0529 or 6.18.21, whichever matches your release line, or a later version.
  2. Update Linux Kernel to 6.18.21 or 6.19.11, whichever matches your release line, or a later version.

Affected products and versions

VendorProductAffected versionsFixed in
LinuxLinux4c03342e5ac532fb34d13a7b51dd7261dfc48963 up to, but not including, a17443af874229408ce6b78e2c8a2b5adeb4b7d8; d00ce96623a69a100ad79675d0e85fda3c50d89b up to, but not including, 0d15c3611a2cc5d08993545d4032055ae10ae2c1; 9d21199842247ab05c675fb9b6c6ca393a5c0024 up to, but not including, a3125bc01884431d30d731461634c8295b6f0529; 6.18.17 up to, but not including, 6.18.21; 6.19.7 up to, but not including, 6.19.11a17443af874229408ce6b78e2c8a2b5adeb4b7d8, 0d15c3611a2cc5d08993545d4032055ae10ae2c1, a3125bc01884431d30d731461634c8295b6f0529, 6.18.21, 6.19.11
LinuxLinux Kernel6.18.17 up to, but not including, 6.18.21; 6.19.7 up to, but not including, 6.19.11; 7.06.18.21, 6.19.11

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
LocalThe attacker needs local access or must trick a user into running something.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Privileges required
LowA basic user account is enough.
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
HighData or code can be modified at will.
Availability
HighThe component can be taken down completely.

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

Official description

In the Linux kernel, the following vulnerability has been resolved: bpf: Reset register ID for BPF_END value tracking When a register undergoes a BPF_END (byte swap) operation, its scalar value is mutated in-place. If this register previously shared a scalar ID with another register (e.g., after an `r1 = r0` assignment), this tie must be broken. Currently, the verifier misses resetting `dst_reg->id` to 0 for BPF_END. Consequently, if a conditional jump checks the swapped register, the verifier incorrectly propagates the learned bounds to the linked register, leading to false confidence in the linked register's value and potentially allowing out-of-bounds memory accesses. Fix this by explicitly resetting `dst_reg->id` to 0 in the BPF_END case to break the scalar tie, similar to how BPF_NEG handles it via `__mark_reg_known`.

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. Record last changed materially (score, affected products, status or references).

References

Recent Out-of-bounds Read vulnerabilities

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