Strix
57.3K

CVE-2026-74657

Unknown

Last modified

CVE-2026-74657 is a vulnerability of currently unknown severity. In the Linux kernel, the following vulnerability has been resolved: ipv4: Fix fib_nlmsg_size() for RTA_VIA nexthops fib_nlmsg_size() still estimates nexthop space as if every gateway is encoded as an IPv4 RTA_GATEWAY attribute. IPv4 routes can also carry an IPv6 gateway, which fib_nexthop_info() dumps as RTA_VIA. As a result, route notifications can allocate an skb that is too small. fib_dump_info() then fails with -EMSGSIZE and rtmsg_fib() hits the WARN_ON() that marks such failures as a fib_nlmsg_size() bug.

Description

In the Linux kernel, the following vulnerability has been resolved: ipv4: Fix fib_nlmsg_size() for RTA_VIA nexthops fib_nlmsg_size() still estimates nexthop space as if every gateway is encoded as an IPv4 RTA_GATEWAY attribute. IPv4 routes can also carry an IPv6 gateway, which fib_nexthop_info() dumps as RTA_VIA. As a result, route notifications can allocate an skb that is too small. fib_dump_info() then fails with -EMSGSIZE and rtmsg_fib() hits the WARN_ON() that marks such failures as a fib_nlmsg_size() bug. With panic_on_warn set, this becomes a kernel panic. Mirror the actual nexthop dump layout in fib_nlmsg_size(): account for IPv6 nexthop gateways dumped as RTA_VIA, for the no-header rtnexthop layout used inside RTA_MULTIPATH, and for RTA_FLOW only when it is actually present.

Affected Software

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

VendorProductVersions
LinuxLinux>= d15662682db232da77136cd348f4c9df312ca6f9, < 0f0ca602941d0a81ae9514943ca06c55159c6385; >= d15662682db232da77136cd348f4c9df312ca6f9, < 5307a53599fa762c06e475ee4a375252074fd324; >= d15662682db232da77136cd348f4c9df312ca6f9, < 7f80ad373ce4a7af5367ff273cea0f16e91387f3; >= d15662682db232da77136cd348f4c9df312ca6f9, < 4a5dfbae5179f6574695012a980476254df2d295; >= d15662682db232da77136cd348f4c9df312ca6f9, < a59edda6eda1252340354322d8ab318b2e9052fb; >= d15662682db232da77136cd348f4c9df312ca6f9, < 9b22f13524fa0de0d963bbd3002df6c28bae3395; >= d15662682db232da77136cd348f4c9df312ca6f9, < 4ff9548d84945d2cbf9e4c207288063a200ea397
LinuxLinux5.2

References

Timeline

Published
Last Modified
Status
Received

Frequently Asked Questions

What is CVE-2026-74657?
In the Linux kernel, the following vulnerability has been resolved: ipv4: Fix fib_nlmsg_size() for RTA_VIA nexthops fib_nlmsg_size() still estimates nexthop space as if every gateway is encoded as an IPv4 RTA_GATEWAY attribute. IPv4 routes can also carry an IPv6 gateway, which fib_nexthop_info() dumps as RTA_VIA. As a result, route notifications can allocate an skb that is too small. fib_dump_info() then fails with -EMSGSIZE and rtmsg_fib() hits the WARN_ON() that marks such failures as a fib_nlmsg_size() bug. With panic_on_warn set, this becomes a kernel panic. Mirror the actual nexthop dump layout in fib_nlmsg_size(): account for IPv6 nexthop gateways dumped as RTA_VIA, for the no-header rtnexthop layout used inside RTA_MULTIPATH, and for RTA_FLOW only when it is actually present.
How severe is CVE-2026-74657?
Severity scoring for CVE-2026-74657 is pending analysis.
How do I fix CVE-2026-74657?
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.

How Strix Helps

Related CVEs from 2026

View all 2026CVEs →

Are you affected by CVE-2026-74657?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST