Out-of-bounds Read in Linux
CVE-2026-43070
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`.
Vulnerability class: Buffer Overflow
Published · last modified .
CVSS v3 metric
CVSS v3 base score 7.8 (High). Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.
EPSS exploit prediction
EPSS: 0.002 (6.0th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 6th percentile — 6.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.001 · newest: 0.002 · change: +0.001
Affected products
- Linux — versions 4c03342e5ac532fb34d13a7b51dd7261dfc48963, d00ce96623a69a100ad79675d0e85fda3c50d89b, 9d21199842247ab05c675fb9b6c6ca393a5c0024
- Linux Kernel — versions 7.0
Weakness classification (CWE)
References
Frequently asked questions
- What is CVE-2026-43070?
- CVE-2026-43070 is a high-severity vulnerability in Linux, classified under Out-of-bounds Read. CVSS score: 7.8/10. Published 2026-05-05.
- How severe is CVE-2026-43070?
- High severity. CVSS v3 base score is 7.8 out of 10.