CVE-2026-23270 Affecting kernel-source package, versions <6.12.0-160000.28.1


Severity

Recommended
0.0
medium
0
10

Based on SUSE Linux Enterprise Server security rating.

Threat Intelligence

EPSS
0.01% (4th percentile)

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  • Snyk IDSNYK-SLES1600-KERNELSOURCE-16332767
  • published1 May 2026
  • disclosed20 Apr 2026

Introduced: 20 Apr 2026

NewCVE-2026-23270  (opens in a new tab)

How to fix?

Upgrade SLES:16.0.0 kernel-source to version 6.12.0-160000.28.1 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel-source package and not the kernel-source package as distributed by SLES. See How to fix? for SLES:16.0.0 relevant fixed versions and status.

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

net/sched: Only allow act_ct to bind to clsact/ingress qdiscs and shared blocks

As Paolo said earlier [1]:

"Since the blamed commit below, classify can return TC_ACT_CONSUMED while the current skb being held by the defragmentation engine. As reported by GangMin Kim, if such packet is that may cause a UaF when the defrag engine later on tries to tuch again such packet."

act_ct was never meant to be used in the egress path, however some users are attaching it to egress today [2]. Attempting to reach a middle ground, we noticed that, while most qdiscs are not handling TC_ACT_CONSUMED, clsact/ingress qdiscs are. With that in mind, we address the issue by only allowing act_ct to bind to clsact/ingress qdiscs and shared blocks. That way it's still possible to attach act_ct to egress (albeit only with clsact).

[1] https://lore.kernel.org/netdev/674b8cbfc385c6f37fb29a1de08d8fe5c2b0fbee.1771321118.git.pabeni@redhat.com/ [2] https://lore.kernel.org/netdev/cc6bfb4a-4a2b-42d8-b9ce-7ef6644fb22b@ovn.org/

CVSS Base Scores

version 3.1