Live › vulnerability › CVE-2026-98794
Go to dashboardThe Linux kernel's IPVS sync handling on a backup server accepted connection flag combinations (NO_CPORT with TEMPLATE, and ONE_PACKE from protocol v0 messages) that can break connection lookups. The sources do not say what an attacker can obtain beyond disruption of the backup server.
Summary written from the sources below. Check the originals before acting.
First seen by InfraStack 2026-10-23 21:57 UTC. All times on this page are UTC.
Only hosts running IPVS load balancing with connection synchronization (the backup role receiving sync messages from a master) are relevant. Systems without IPVS or without sync daemons configured are not exposed through this path. The sources do not name specific distributions or versions.
No product ranges from the sources yet.
uname -r and compare with the fixed kernel version in the vendor advisory: unknownlsmod | grep ip_vs to see whether IPVS is loaded on the host: unknownEach row is the first time that source carried this signal. The analyst’s rows are its own findings.
In the Linux kernel, the following vulnerability has been resolved:
ipvs: filter some flags received in the backup server
While the IPVS SYNC protocol is not secure by design we can still protect the backup server from messages that can wreak havoc.
This commit addresses problems from received connection flags or their combinations. We now drop messages as follows:
the NO_CPORT+TEMPLATE combination allows lookups for normal connections to hit template which can break in many ways. While the master does not sync connections with NO_CPORT flag, i.e. before they are established, we still accept NO_CPORT without TEMPLATE.
ONE_PACKET: it is not sent by master, so we do not expect it in backup. Before now it was ignored by IP_VS_CONN_F_BACKUP_MASK for protocol v1 while protocol v0 created connections that are not hashed and dropped immediately. Better to apply the IP_VS_CONN_F_BACKUP_MASK also to the flags from v0 messages for consistency with v1.
This page as .md · .json · in your agent: get_signal("CVE-2026-98794")
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