Invalid kernel memory access via VXLAN FDB race
Published Sep 4, 2026 · Updated Sep 4, 2026
Race condition in Linux kernel VXLAN 6.7 and later affected branches allows attackers to trigger invalid kernel memory access. vxlan_fdb_dst_destroy() unlinks the last remote before vxlan_flush() removes the parent FDB entry, so first_remote_rcu() derives an invalid pointer from an empty list head. Reachability requires a filtered bulk flush matching every remote while an RCU receive-learning reader accesses the still-indexed parent; the published record does not establish code execution or privilege escalation.
Summary
What happened
Race condition in Linux kernel VXLAN 6.7 and later affected branches allows attackers to trigger invalid kernel memory access. vxlan_fdb_dst_destroy() unlinks the last remote before vxlan_flush() removes the parent FDB entry, so first_remote_rcu() derives an invalid pointer from an empty list head. Reachability requires a filtered bulk flush matching every remote while an RCU receive-learning reader accesses the still-indexed parent; the published record does not establish code execution or privilege escalation.
The record
- CVE
- CVE-2026-80838
- Published
- Sep 4, 2026
- Updated
- Sep 4, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux
- Classifications
- Unavailable
- Attack vector
- Unavailable
- Privileges
- Unavailable
Timeline
How it unfolded
- Sep 4, 2026CVE publishedPublication date reported by the CVE source.
- Sep 4, 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=6.7
- Affected versionversion=c499fccb71cb85902b5c5b9ce9c9ae6683e54a8f <2a7c2f00843225d5f037676bca649321f3d024c7
- Affected versionversion=c499fccb71cb85902b5c5b9ce9c9ae6683e54a8f <4bbc76ee1b21d3bd045d6d819b2bacd30a6372ab
- Affected versionversion=c499fccb71cb85902b5c5b9ce9c9ae6683e54a8f <8ba68fd6cdd1e3c92b92f25c7e48bf7bd51a183c
- Affected versionversion=c499fccb71cb85902b5c5b9ce9c9ae6683e54a8f <a8820c8a7718327e96849782033e7c85a0f6bcfe
- Affected versionversion=c499fccb71cb85902b5c5b9ce9c9ae6683e54a8f <d5d4a7b538b52db63927773a8905fcd9f78a42e2
What conditions does exploitation require?
What is affected?
Published CVSS scores
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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.
Weakness, pattern, technique
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Public exploit references
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Technologies
Your stack
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Your stack
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