---
id: CVE-2026-90246
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  apparmor: fix integer overflow in verify_tags() bounds check

  verify_tags() validates the tagset table unpacked from a policy blob.
  For each set it reads a count and ch…
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  apparmor: fix integer overflow in verify_tags() bounds check

  verify_tags() validates the tagset table unpacked from a policy blob.
  For each set it reads a count and ch…
severity: high
cvss: 7.1
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H'
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 3d28e2397af7a89ac3de33c686ed404cda59b5d5 <
    ef79a405f83993f0fda5efde371d98433f7d7a47
  - >-
    Linux >= 3d28e2397af7a89ac3de33c686ed404cda59b5d5 <
    465946d3c560c0137e6a180ba054dddc4d049f5a
  - Linux 7.0
published: '2026-09-17'
updated: '2026-09-18'
sourceUpdated: '2026-09-18T18:17:50.873'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-90246'
references:
  - url: 'https://git.kernel.org/stable/c/465946d3c560c0137e6a180ba054dddc4d049f5a'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/ef79a405f83993f0fda5efde371d98433f7d7a47'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
tags:
  - nvd
  - cve.org
epss: 0.00159
epssPercentile: 0.05451
ingestedAt: '2026-09-17T16:21:47.845Z'
---

## Overview

In the Linux kernel, the following vulnerability has been resolved:

apparmor: fix integer overflow in verify_tags() bounds check

verify_tags() validates the tagset table unpacked from a policy blob.
For each set it reads a count and checks that advancing the index by
that count stays inside sets.table[]:

	u32 cnt = tags->sets.table[i];

	if (i+cnt >= tags->sets.size) {

i, cnt and sets.size are all u32, so i+cnt is evaluated modulo 2^32.
sets.table[] is filled by unpack_tagsets() with aa_unpack_u32(), so
every entry is a raw unbounded 32-bit word taken from the policy blob,
and verify_tags() is the function that is supposed to validate it.  A
count close to U32_MAX makes the sum wrap to a small value, the guard
passes, and the inner loop then walks sets.table[++i] past the end of
the kcalloc(size, sizeof(u32)) allocation.

Note that sets.size is bounded by 65535, because unpack_tagsets() reads
it with aa_unpack_array() as a u16, so the wrap cannot be reached by
growing the table; it is reached purely through the attacker-supplied
count.

With sets.size = 2 and sets.table = { 0, 0xffffffff }:

  i = 0: cnt = 0, guard 0 + 0 >= 2 is false, inner loop does not run
  i = 1: cnt = 0xffffffff, guard (1 + 0xffffffff) mod 2^32 == 0 >= 2 is
         false, so the guard is bypassed and the inner loop reads
         sets.table[2] -- one element past a two element allocation

The walk continues until an out-of-bounds value happens to be >=
hdrs.size or the access faults, so a crafted policy yields an
out-of-bounds read on the policy load path
(aa_replace_profiles -> aa_unpack -> unpack_policydb -> unpack_tags ->
verify_tags).  unpack_tags() runs before the perms and DFA tables are
unpacked, so no other table needs to be well formed to reach it.

Policy load is gated by aa_may_manage_policy(), which checks
CAP_MAC_ADMIN relative to the subject's own user namespace rather than
the init user namespace, so with the default
unprivileged_userns_apparmor_policy=1 the path is reachable from an
unprivileged task in a matched-level nested namespace, not only by a
globally privileged one.

Perform the addition in u64 so that it cannot wrap, restoring the
intended i + cnt < sets.size guarantee.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.