CVE-2026-97596: ipvs: reject invalid states in connection template sync records
In the Linux kernel, the following vulnerability has been resolved:
ipvs: reject invalid states in connection template sync records
IPVS sync receivers validate protocol states before creating or updating a connection. For connection templates, however, they only log states outside the template state range and still store the value in the connection.
A template can be returned by ordinary connection lookup. TCP and SCTP then use the invalid state as an index into their transition tables.
Reject invalid template states in both sync protocol versions before looking up or modifying a connection. The version 1 path handles both IPv4 and IPv6 records.
Affected Software
Event History
Frequently Asked Questions
Which systems are exposed to this issue?
Systems using Linux IPVS sync receivers are affected when they process connection template sync records. The issue applies to both sync protocol versions; version 1 covers IPv4 and IPv6 records.
What conditions are needed for the fault to be reached?
A sync receiver must accept a connection template record with a state outside the valid template-state range. If that template is later returned by an ordinary connection lookup, TCP or SCTP can use the invalid state as an index into a transition table.
Can existing logging prevent the issue?
No. The affected behavior logs out-of-range template states but still stores them in the connection, so logging alone does not prevent later use of the invalid value.