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.

Project Subscriptions

Vendors Products
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Advisories
Source ID Title
Debian DLA Debian DLA DLA-4850-1 linux-6.12 security update
Debian DSA Debian DSA DSA-6568-1 linux security update
Fixes

Solution

No solution given by the vendor.


Workaround

No workaround given by the vendor.

History

Fri, 30 Oct 2026 12:45:00 +0000


Wed, 21 Oct 2026 13:15:00 +0000


Sat, 03 Oct 2026 11:15:00 +0000


Thu, 01 Oct 2026 08:45:00 +0000

Type Values Removed Values Added
Weaknesses CWE-400

Wed, 30 Sep 2026 00:15:00 +0000

Type Values Removed Values Added
References
Metrics threat_severity

None

cvssV3_1

{'score': 5.5, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'}

threat_severity

Low


Fri, 25 Sep 2026 14:00:00 +0000

Type Values Removed Values Added
Weaknesses CWE-400
CWE-770

Fri, 25 Sep 2026 10:30:00 +0000

Type Values Removed Values Added
Description 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.
Title ipv6: flowlabel: cap duplicate leases per socket
First Time appeared Linux
Linux linux Kernel
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
References

Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: Linux

Published:

Updated: 2026-10-30T12:37:32.857Z

Reserved: 2026-09-24T16:01:01.157Z

Link: CVE-2026-97597

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-09-25T11:17:11.017

Modified: 2026-10-30T13:21:09.117

Link: CVE-2026-97597

cve-icon Redhat

Severity : Low

Publid Date: 2026-09-25T00:00:00Z

Links: CVE-2026-97597 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2026-10-01T11:00:06Z

Weaknesses