Host crash via lost qdisc fragment metadata
Published Aug 15, 2026 · Updated Aug 15, 2026
Reachable assertion in the Linux kernel allows remote attackers to crash hosts via fragmented traffic through a configured act_ct action. tcf_ct_handle_fragments() fails to preserve skb->cb while nf_ct_handle_fragments() clears an aliased control buffer, erasing qdisc metadata such as pkt_segs. The path is exposed only where act_ct processes the fragments, and a crash requires panic_on_warn; otherwise packet accounting or handling is corrupted.
Summary
What happened
Reachable assertion in the Linux kernel allows remote attackers to crash hosts via fragmented traffic through a configured act_ct action. tcf_ct_handle_fragments() fails to preserve skb->cb while nf_ct_handle_fragments() clears an aliased control buffer, erasing qdisc metadata such as pkt_segs. The path is exposed only where act_ct processes the fragments, and a crash requires panic_on_warn; otherwise packet accounting or handling is corrupted.
The record
- CVE
- CVE-2026-72057
- Published
- Aug 15, 2026
- Updated
- Aug 15, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux
- Classifications
- CWE-617, T1499
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Aug 15, 2026CVE publishedPublication date reported by the CVE source.
- Aug 15, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=0d76daf2013ce1da20eab5e26bd81d983e1c18fb
- Affected versionversion=5.15.13 <5.16
- Affected versionversion=5.16
- Affected versionversion=ec624fe740b416fb68d536b37fb8eef46f90b5c2 <2400c4b05d58834b994500a9eec90a37db44187c
- Affected versionversion=ec624fe740b416fb68d536b37fb8eef46f90b5c2 <5c3ae5f6c7c6de73ea9b6a75154fe4ed343e1bac
- Affected versionversion=ec624fe740b416fb68d536b37fb8eef46f90b5c2 <9092e15defbe6c7bc241c306093ca9d358a578e7
- Affected versionversion=ec624fe740b416fb68d536b37fb8eef46f90b5c2 <b3d835407846134b0d54637c0281b39bebef831d
- Affected versionversion=ec624fe740b416fb68d536b37fb8eef46f90b5c2 <f7f45ceb855d9ba1cba594fb3f383255f7013fad
What conditions does exploitation require?
What is affected?
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Public exploit references
No public exploit references are available in this record.
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Technologies
Your stack
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Your stack
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