CVE-2026-23270 | net/sched: Only allow act_ct to bind to clsact/ingress qdiscs and shared blocks

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/[email protected]/

Published: 2026-03-18 Last update: 2026-06-17 Assigner: 416baaa9-dc9f-4396-8d5f-8c081fb06d67 Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
NVD Status：Analyzed，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2026-23270 is rated Low Risk (32.1/100): CVSS High severity, with low exploitation likelihood (EPSS 0.12%). Monitor for updates and reassess as exploit intelligence or EPSS changes.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2026-23270

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 0.02% 0.12% +0.10%
2 2026-03-19 — 0.02% —

Full EPSS history (2 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2026-23270

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.8 3.1 HIGH
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H Click to expand
Attack vector (AV:L)
They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 1.8 5.9 416baaa9-dc9f-4396-8d5f-8c081fb06d67

Weakness enumeration for CVE-2026-23270

GitHub Security Advisory for CVE-2026-23270

GHSA-62jp-jvc3-7hh9 · Severity: high — In the Linux kernel, the following vulnerability has been resolved: net/sched: Only allow act_ct...

OS Trackers for CVE-2026-23270

vendor priority summary link
debian unimportant CVE-2026-23270 unimportant priority: Debian including 2 source packages (linux, linux-6.1), 6 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 6. https://security-tracker.debian.org/tracker/CVE-2026-23270
redhat medium — https://access.redhat.com/security/cve/CVE-2026-23270
suse medium CVE-2026-23270 severity moderate: SUSE including 61 source package names (2.1.3-6.144:kernel-default-base-6.4.0-41.1.21.18, 2.1.3-7.127:kernel-default-6.4.0-41.1, …), 149 product×package rows across 35 product lines (Container suse/sl-micro/6.0/base-os-container, Container suse/sl-micro/6.0/kvm-os-container, … (35 product lines)): Known Not Affected 99, First Fixed 30, Fixed 20. https://www.suse.com/security/cve/CVE-2026-23270/
ubuntu medium CVE-2026-23270 medium priority: Ubuntu including 157 source packages (linux, linux-allwinner-5.19, …), 1256 status rows across 8 suites (bionic, focal, jammy, noble, questing, trusty, upstream, xenial): DNE 871, ignored 169, needed 87, released 83, not-affected 46. https://ubuntu.com/security/CVE-2026-23270

Affected software / configurations for CVE-2026-23270

Vendor Product Version Raw CPE
linux linux_kernel >= 5.15.148, < 5.15.203 cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
linux linux_kernel >= 6.1.75, < 6.1.167 cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
linux linux_kernel >= 6.6.14, < 6.6.130 cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
linux linux_kernel >= 6.7.2, < 6.8 cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
linux linux_kernel >= 6.8, < 6.12.77 cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
linux linux_kernel >= 6.13, < 6.18.18 cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
linux linux_kernel >= 6.19, < 6.19.8 cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
linux linux_kernel 7.0 cpe:2.3:o:linux:linux_kernel:7.0:rc1:*:*:*:*:*:*
linux linux_kernel 7.0 cpe:2.3:o:linux:linux_kernel:7.0:rc2:*:*:*:*:*:*

References for CVE-2026-23270

cvelogic Threat Intelligence