What is CVE-2026-43070?

CVE-2026-43070 is a High severity Linux kernel vulnerability with a CVSS score of 7.8 out of 10, classified as a Out-of-bounds Read flaw (CWE-125), affecting Linux kernel versions from 6.18.17 onward and patched in 6.18.21 and 6.19.11. CVE-2026-43070 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

What is the CVSS score for CVE-2026-43070?

CVE-2026-43070 has a CVSS score of 7.8 out of 10, rated High severity. The vector string is CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.

Is there a patch available for CVE-2026-43070?

Yes, CVE-2026-43070 has been patched. Fixed versions include 6.18.21 and 6.19.11. If you are running Linux kernel 6.18.17 or later up to the fix versions, apply the relevant patch for your kernel branch.

Is CVE-2026-43070 actively exploited?

CVE-2026-43070 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

What is Out-of-bounds Read (CWE-125)?

The product reads data past the end or before the beginning of the intended buffer. See MITRE CWE for full details: https://cwe.mitre.org/data/definitions/125.html

CVE-2026-43070

High

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`.

Package Linux Kernel

Published 2026-05-05

Last modified 2026-05-29

CVSS version 3.1

Patch available

Yes

CVSS 3.1 score

7.8

out of 10

High

Attack Vector

Local

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Vector string

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

Weakness type

CWE-125

CVE-2026-43070 is a Out-of-bounds Read vulnerability

What is Out-of-bounds Read?

The product reads data past the end or before the beginning of the intended buffer. Learn more on MITRE CWE

Affected versions

Linux kernel versions 6.18.17, 6.19.7 and later are affected. Fixed in 6.18.21, 6.19.11 and their respective stable series.

Affected from

≥ 6.18.17 ≥ 6.19.7

Fixed in

✓ 6.18.21 6.18.x ✓ 6.19.11 6.19.x

References

3 total

Kernel Git
https://git.kernel.org/stable/c/0d15c3611a2cc5d08993545d4032055ae10ae2c1

Patch
Kernel Git
https://git.kernel.org/stable/c/a17443af874229408ce6b78e2c8a2b5adeb4b7d8

Patch
Kernel Git
https://git.kernel.org/stable/c/a3125bc01884431d30d731461634c8295b6f0529

Patch

Details

CVE ID CVE-2026-43070

Severity High

CVSS score 7.8 / 10

CVSS version 3.1

Published 2026-05-05

Modified 2026-05-29

KEV No

Patch

Yes

Package linux

Frequently asked questions

What is CVE-2026-43070?

CVE-2026-43070 is a High severity Linux kernel vulnerability with a CVSS score of 7.8 out of 10 , classified as an Out-of-bounds Read flaw (CWE-125) . It affects Linux kernel versions from 6.18.17 onward and has been patched in 6.18.21 and 6.19.11. CVE-2026-43070 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
What is the CVSS score for CVE-2026-43070?

CVE-2026-43070 has a CVSS score of 7.8 out of 10, rated High severity (CVSS 3.1). The vector string is CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.
Is there a patch available for CVE-2026-43070?

Yes. CVE-2026-43070 has been patched. Fixed versions include 6.18.21 and 6.19.11. If you are running Linux kernel 6.18.17 or later up to the fix versions, apply the relevant patch for your kernel branch.
Is CVE-2026-43070 actively exploited?

No. CVE-2026-43070 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.