Low

Linux kernel BPF tc_skb_cb state collision in cls_bpf_classify

IdentifiersCVE-2025-68200CWE-664

CVE-2025-68200 is a Linux kernel vulnerability in the BPF/networking path affecting cls_bpf_classify(). A faulty interaction between net_sched control-block storage in struct tc_skb_cb and BPF data pointer handling introduced a state collision, allowing cls_bpf_classify() to modify tc_skb_cb(skb)->drop_reason unexpectedly. This can trigger a kernel warning in sk_skb_reason_drop() / __sk_skb_reason_drop() in net/core/skbuff.c. The issue stems from the interaction between the tc control block changes introduced by commit ec624fe740b4 and BPF data/data_end wiring from commit db58ba459202; later addition of drop_reason made the collision observable. The fix adds bpf_prog_run_data_pointers() to save and restore net_sched storage that collides with BPF data_meta/data_end.

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ANALYST BRIEF

Impact, mitigation & remediation

What it means. What to do now. Patch path, mitigations, and the assume-compromise checklist.

Impact

What an attacker gets, and what they’ve been doing with it.

The available information indicates a denial-of-service class impact in the Linux kernel networking stack. Successful triggering can corrupt or improperly alter skb control-block state related to drop_reason and cause kernel warnings in sk_skb_reason_drop(). SUSE scores the issue CVSS 5.5 with vector AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H, indicating no confidentiality or integrity impact but high availability impact, consistent with local low-privilege disruption or instability rather than code execution.

Mitigation

If you can’t patch tonight, do this now.

If immediate patching is not possible, reduce exposure by restricting local untrusted users' ability to load or exercise relevant BPF/tc paths, minimizing access to traffic-control and BPF functionality to trusted administrators only. Systems that permit low-privilege local users to interact with affected kernel networking/BPF features are at greater risk. Because the issue is in kernel state handling, mitigation is limited; patching is the primary corrective action.

Remediation

Patch, then assume compromise.

Apply a Linux kernel update containing the upstream fix that introduces bpf_prog_run_data_pointers() and preserves/restores net_sched storage when BPF data_meta/data_end are used. Vendor-fixed package versions cited in the provided content include, for example, kernel-default >= 6.4.0-39.1 for SUSE Linux Micro 6.0/6.1, kernel-rt >= 6.4.0-40.1 for affected SUSE Linux Micro RT variants, kernel-default >= 6.12.0-160000.26.1 for SLES 16.0-related products, and kernel-default >= 6.4.0-150700.53.31.1 for SLES 15 SP7-related products. Use the vendor advisory for the specific distribution and product line to select the correct fixed kernel build.

PUBLIC EXPLOITS

Exploits

No public exploits tracked yet. Mallory keeps watching.

VALID 0 / 0 TOTALView more in app

No public exploit code observed for this vulnerability.

ACTIVITY FEED

Recent activity

4 sources tracked across advisories and community write-ups. News coverage will land here when it surfaces.

4 SOURCESView more in app

No news coverage yet. Advisories and community discussion only.

What this page doesn’t show

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Exposure mapping

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Threat actor evidence

Every observed campaign linking this CVE to a named adversary.

Associated malware

Malware families riding this exploit, with evidence and IOCs.

Detection signatures

YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.

Vendor-by-vendor mapping

Cross-references every affected SKU, including bundled OEM variants.

Social activity3