ipv4: Fix fib_nlmsg_size() for RTA_VIA nexthops (Linux Linux)

CVE-2026-74657
Not available

At a glance

Source
NVD
EPSS
EPSS 0.18 % · percentile 7 ()
State
PUBLISHED
Published
Updated
Assigner
Linux
NVD status
Received

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.

References

European references

CERT-FR advisories

Affected products

ProductVersions
Linux · Linuxaffected d15662682db232da77136cd348f4c9df312ca6f9 < 57195f0ab5cfbb5ee0864e5aff15ceb48f5a5e28 ; affected d15662682db232da77136cd348f4c9df312ca6f9 < 0f0ca602941d0a81ae9514943ca06c55159c6385 ; affected d15662682db232da77136cd348f4c9df312ca6f9 < 5307a53599fa762c06e475ee4a375252074fd324 ; affected d15662682db232da77136cd348f4c9df312ca6f9 < 7f80ad373ce4a7af5367ff273cea0f16e91387f3 ; affected d15662682db232da77136cd348f4c9df312ca6f9 < 4a5dfbae5179f6574695012a980476254df2d295 ; affected d15662682db232da77136cd348f4c9df312ca6f9 < a59edda6eda1252340354322d8ab318b2e9052fb
Linux · Linuxaffected 5.2 ; unaffected 0 < 5.2 ; unaffected 5.10.267 ≤ 5.10.* ; unaffected 5.15.216 ≤ 5.15.* ; unaffected 6.1.183 ≤ 6.1.* ; unaffected 6.6.152 ≤ 6.6.*

Sources

SourceLicence
CVE List (CVEProject cvelistV5)CVE Program Terms of Use
EPSS (FIRST.org)FIRST — attribution requested
ENISA EUVDENISA — reproduction authorised, source acknowledged
CERT-FR (ANSSI)Licence Ouverte / Etalab 2.0
NVD (NIST) via fkie-cad/nvd-json-data-feedsPublic domain — this product uses data from the NVD API but is not endorsed or certified by the NVD