CVE-2023-3812: Kernel: tun: bugs for oversize packet when napi frags enabled in tun_napi_alloc_frags

Severity: high (CVSS 7.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2023-07-24 · updated 2026-06-17
Weakness: CWE-787

Description

An out-of-bounds memory access flaw was found in the Linux kernel’s TUN/TAP device driver functionality in how a user generates a malicious (too big) networking packet when napi frags is enabled. This flaw allows a local user to crash or potentially escalate their privileges on the system.

Affected products

Linux kernel: from 4.15 before 4.19.265; from 4.20 before 5.4.224; from 5.5 before 5.10.154; from 5.11 before 5.15.78; from 5.16 before 6.0.8 — fixed in 4.19.265, 5.10.154, 5.15.78, 5.4.224, 6.0.8
Red Hat Enterprise Linux: 8.0, 9.0

How to fix

Upgrade to a fixed version: Linux kernel 4.19.265, 5.10.154, 5.15.78, 5.4.224. Check the vendor advisory for mitigations.

References

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