---
id: CVE-2026-97597
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  ipv6: flowlabel: cap duplicate leases per socket

  ipv6_flowlabel_get() allocates an ipv6_fl_socklist entry for every
  successful GET
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  ipv6: flowlabel: cap duplicate leases per socket

  ipv6_flowlabel_get() allocates an ipv6_fl_socklist entry for every
  successful GET. The recheck path for a compatible e…
severity: none
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <
    2f1a6dd5c80ceb902f50449efe899f29cd7918e3
  - >-
    Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <
    467467bf4209f9f8add0c648bae763f92a0224c3
  - >-
    Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <
    8d6cd188508513503805c156165de38e4e4a8615
  - Linux 2.6.12
published: '2026-09-25'
updated: '2026-09-25'
sourceUpdated: '2026-09-25T11:17:11.017'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-97597'
references:
  - url: 'https://git.kernel.org/stable/c/2f1a6dd5c80ceb902f50449efe899f29cd7918e3'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/467467bf4209f9f8add0c648bae763f92a0224c3'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/8d6cd188508513503805c156165de38e4e4a8615'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
tags:
  - nvd
  - cve.org
ingestedAt: '2026-09-25T11:06:38.904Z'
---

## Overview

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

ipv6: flowlabel: cap duplicate leases per socket

ipv6_flowlabel_get() allocates an ipv6_fl_socklist entry for every
successful GET. The recheck path for a compatible existing flowlabel
links another lease without applying any lease admission check. Repeated
GET requests for one shareable label can therefore grow a socket's lease
list without bound.

Reject a new unprivileged lease once the socket already holds
FL_MAX_PER_SOCK leases. Check this on the shared recheck path so reuse
of a globally interned label, including the fl_intern() collision path,
is covered as well. New-label admission remains under the existing
mem_check() policy.

Use capable(CAP_NET_ADMIN) rather than ns_capable(), matching
mem_check(). An unprivileged user must not bypass the cap by creating a
user namespace and a netns where they have CAP_NET_ADMIN, which would
still consume host memory.

Check the capability only when the socket reaches the limit, so
successful unprivileged GET requests below the cap do not generate a
capability audit. Do the admission check before updating linger and
expires so a rejected GET does not refresh the shared label, matching
the existing socket-list allocation failure path.

## Remediation

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