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NVD / CVE Program· CNA Linux

CVE-2026-68441: net/sched: Handle TC_ACT_REDIRECT from qdisc filter chains

Noroxi assessment

Priority: Monitor (action score 0/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.16% (FIRST EPSS).
  • Fixed version: Linux Linux 636658e50b5c6a2c93413a9fa6d9da768dbfdaf2, 98ca831065c4d20baf97dc9e232777dc47a2b923, 9cbad9c8125f5fe377c0800ab08f7196eab44456; azl3 kernel 6.6.152.1-1 on Azure Linux 3.0 Release Notes; azl3 kernel 6.6.157.1-1 on Azure Linux 3.0 Release Notes.

Low priority for now. Upgrade to Linux Linux 636658e50b5c6a2c93413a9fa6d9da768dbfdaf2, 98ca831065c4d20baf97dc9e232777dc47a2b923, 9cbad9c8125f5fe377c0800ab08f7196eab44456; azl3 kernel 6.6.152.1-1 on Azure Linux 3.0 Release Notes; azl3 kernel 6.6.157.1-1 on Azure Linux 3.0 Release Notes or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

In the Linux kernel, the following vulnerability has been resolved: net/sched: Handle TC_ACT_REDIRECT from qdisc filter chains When a TC filter attached to a qdisc filter chain returns TC_ACT_REDIRECT (ex: via an eBPF program calling bpf_redirect() or an act_bpf action), the redirect was silently lost i.e no qdisc classify function handled TC_ACT_REDIRECT, so the packet fell through the switch and was enqueued normally instead of being redirected. This has been broken since bpf_redirect() was introduced for TC in commit 27b29f63058d ("bpf: add bpf_redirect() helper"). We got lucky for a long time because bpf_net_context was a per-CPU variable that was always available. commit 401cb7dae813 ("net: Reference bpf_redirect_info via task_struct on PREEMPT_RT.") turned bpf_net_context into a task_struct member that is only set up by explicit callers. Without a caller setting it up, bpf_redirect() itself crashes with a NULL pointer dereference in bpf_net_ctx_get_ri(). However, even with bpf_net_context available, TC_ACT_REDIRECT from qdisc filter chains cannot be honored without adding skb_do_redirect() calls to every qdisc classify function, which would require changes across net/sched/. Isolate it to ebpf core where it belongs. Instead, add a tcf_classify_qdisc() inline helper in pkt_cls.h, as a wrapper around tcf_classify() for use by qdisc classify functions and tcf_qevent_handle(). When the classify verdict is TC_ACT_REDIRECT, the wrapper converts it to TC_ACT_SHOT, dropping the packet rather than letting it continue silently. Dropping is preferred over letting the packet through because the user immediately sees packet loss. Silently passing the packet through would hide the problem and leave the user wondering why their redirect is not working. The clsact fast path, tc_run() continues to call tcf_classify() directly and is unaffected: TC_ACT_REDIRECT is returned as-is and handled by sch_handle_egress/ingress() calling skb_do_redirect() as before.

—No exploit Fix available
Published
Aug 12, 2026
Updated
Oct 21, 2026
EPSS
0.1% · 5th percentile
CWE
—

Report tools

JSON

Action score

0

Monitor

Low priority for now.

CVSS
0 / 40 · —
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.1%

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Noroxi analysis

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

—

Versions reported by the vendor

Affected version ranges reported by the assigning authority (Linux). Independent of NVD's CPE analysis and usually ahead of it.

  • Linux Linux

    • 4.4affected
    • 27b29f63058d26c6c1742f1993338280d5a41dc6 and later · before 98ca831065c4d20baf97dc9e232777dc47a2b923affected · git
    • 27b29f63058d26c6c1742f1993338280d5a41dc6 and later · before 636658e50b5c6a2c93413a9fa6d9da768dbfdaf2affected · git
    • 27b29f63058d26c6c1742f1993338280d5a41dc6 and later · before 9cbad9c8125f5fe377c0800ab08f7196eab44456affected · git
    • 27b29f63058d26c6c1742f1993338280d5a41dc6 and later · before c8fd74445e86f88096d2f6cf0f9e4d54d8ed1781affected · git
    • 27b29f63058d26c6c1742f1993338280d5a41dc6 and later · before ec48b3be2c8595dd290be883dbd4fb8b2f9f5d5eaffected · git
    • before 4.4not affected · semver
    • 6.6.160 and later · up to and including 6.6.*not affected · semver
    • 6.12.114 and later · up to and including 6.12.*not affected · semver
    • 6.18.57 and later · up to and including 6.18.*not affected · semver

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:12linuxfrom 0—
Debian:14linuxbefore 7.1.6-17.1.6-1

Other highest-scoring records for the same primary product.

  • CVE-2026-74705udp: fix potential use-after-free in tunnel segmentation
    40Plan
  • CVE-2026-74612veth: fix skb length accounting after XDP frag adjustment
    40Plan
  • CVE-2026-74475vxlan: use neigh_ha_snapshot() in route_shortcircuit()
    40Plan

Published before and after this one in the same product

  • ← EarlierCVE-2026-68435Aug 12, 2026 · LoongArch: Fix address space mismatch in kexec command line lookup
    0Monitor
  • ← EarlierCVE-2026-68436Aug 12, 2026 · drm/amd/display: use kvzalloc to allocate struct dc
    0Monitor
  • Later →CVE-2026-68442Aug 12, 2026 · btrfs: don't propagate EXTENT_FLAG_LOGGING to split extent maps
    31Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Linux Linux636658e50b5c6a2c93413a9fa6d9da768dbfdaf2Vendor (CNA)
Linux Linux98ca831065c4d20baf97dc9e232777dc47a2b923Vendor (CNA)
Linux Linux9cbad9c8125f5fe377c0800ab08f7196eab44456Vendor (CNA)
Linux Linuxc8fd74445e86f88096d2f6cf0f9e4d54d8ed1781Vendor (CNA)
Linux Linuxec48b3be2c8595dd290be883dbd4fb8b2f9f5d5eVendor (CNA)
azl3 kernel 6.6.152.1-1 on Azure Linux 3.0Release NotesMicrosoft (MSRC)
azl3 kernel 6.6.157.1-1 on Azure Linux 3.0Release NotesMicrosoft (MSRC)
debian:linux7.1.6-1 · Debian:14Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

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Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

No CVSS vector for this record, so attack conditions can't be derived.

Weakness class (CWE)

—

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

  1. Fix✗ → ✓

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References

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