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CVE-2026-80838

UnknownEPSS 0.17%

Last modified

CVE-2026-80838 is a vulnerability of currently unknown severity. In the Linux kernel, the following vulnerability has been resolved: vxlan: keep the last remote linked during FDB flush A non-nexthop FDB entry is expected to have at least one remote while it remains reachable through the FDB hash table. A filtered bulk flush violates this invariant when every remote matches: It unlinks the last remote in vxlan_fdb_dst_destroy() and only afterwards tells vxlan_flush() to destroy the parent FDB entry. An RCU reader can find the parent during this interval. first_remote_rcu() then applies list_entry_rcu() to the empty list head, producing an invalid remote pointer that the receive learning path can read from and write to. When a matching remote is the sole remaining remote, leave it linked and ask the caller to destroy the entire FDB entry. EPSS estimates a 0.17% chance of exploitation in the next 30 days.

Description

In the Linux kernel, the following vulnerability has been resolved: vxlan: keep the last remote linked during FDB flush A non-nexthop FDB entry is expected to have at least one remote while it remains reachable through the FDB hash table. A filtered bulk flush violates this invariant when every remote matches: It unlinks the last remote in vxlan_fdb_dst_destroy() and only afterwards tells vxlan_flush() to destroy the parent FDB entry. An RCU reader can find the parent during this interval. first_remote_rcu() then applies list_entry_rcu() to the empty list head, producing an invalid remote pointer that the receive learning path can read from and write to. When a matching remote is the sole remaining remote, leave it linked and ask the caller to destroy the entire FDB entry. vxlan_fdb_destroy() keeps the remote attached while sending the deletion notification and removing the parent from the lookup structures.

Metrics

EPSS Probability
0.17%

5.7th percentile

Probability of exploitation in the next 30 days. Learn more

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

VendorProductVersions
LinuxLinux>= c499fccb71cb85902b5c5b9ce9c9ae6683e54a8f, < 2a7c2f00843225d5f037676bca649321f3d024c7; >= c499fccb71cb85902b5c5b9ce9c9ae6683e54a8f, < a8820c8a7718327e96849782033e7c85a0f6bcfe; >= c499fccb71cb85902b5c5b9ce9c9ae6683e54a8f, < 8ba68fd6cdd1e3c92b92f25c7e48bf7bd51a183c; >= c499fccb71cb85902b5c5b9ce9c9ae6683e54a8f, < 4bbc76ee1b21d3bd045d6d819b2bacd30a6372ab; >= c499fccb71cb85902b5c5b9ce9c9ae6683e54a8f, < d5d4a7b538b52db63927773a8905fcd9f78a42e2
LinuxLinux6.7

References

Timeline

Published
Last Modified
Status
Received

Frequently Asked Questions

What is CVE-2026-80838?
In the Linux kernel, the following vulnerability has been resolved: vxlan: keep the last remote linked during FDB flush A non-nexthop FDB entry is expected to have at least one remote while it remains reachable through the FDB hash table. A filtered bulk flush violates this invariant when every remote matches: It unlinks the last remote in vxlan_fdb_dst_destroy() and only afterwards tells vxlan_flush() to destroy the parent FDB entry. An RCU reader can find the parent during this interval. first_remote_rcu() then applies list_entry_rcu() to the empty list head, producing an invalid remote pointer that the receive learning path can read from and write to. When a matching remote is the sole remaining remote, leave it linked and ask the caller to destroy the entire FDB entry. vxlan_fdb_destroy() keeps the remote attached while sending the deletion notification and removing the parent from the lookup structures.
How severe is CVE-2026-80838?
Severity scoring for CVE-2026-80838 is pending analysis. The EPSS model estimates a 0.17% probability of exploitation in the next 30 days.
How do I fix CVE-2026-80838?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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Source: NVD / NIST