CVE-2026-74657ipv4: Fix fib_nlmsg_size() for RTA_VIA nexthops
- —Not scoredno CVSS score yet
- 0.18%Exploitation in 30 daysEPSS · top 93% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- NonePublic exploitsnone known yet
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.
Timeline
ID reserved
By Linux
- 7 days later
· 7 days later
Published
- 3 months later
· 3 months later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
No CVSS score yet: neither the CNA, CISA nor NVD has scored this CVE. NVD status: Received.
- EPSS (exploitation in 30 days)
- 0.18% · top 93% of all CVEs (13 Nov 2026)
- CISA SSVC
- Exploitation: none · Automatable: no · Technical impact: partial
The list uses the assigner's score when there is one, then CISA's, then NVD's: Not scored.
Affected products
- affected d15662682db232da77136cd348f4c9df312ca6f9 – < 57195f0ab5cfbb5ee0864e5aff15ceb48f5a5e28
- affected d15662682db232da77136cd348f4c9df312ca6f9 – < 0f0ca602941d0a81ae9514943ca06c55159c6385
- affected d15662682db232da77136cd348f4c9df312ca6f9 – < 5307a53599fa762c06e475ee4a375252074fd324
- affected d15662682db232da77136cd348f4c9df312ca6f9 – < 7f80ad373ce4a7af5367ff273cea0f16e91387f3
- affected d15662682db232da77136cd348f4c9df312ca6f9 – < 4a5dfbae5179f6574695012a980476254df2d295
- affected d15662682db232da77136cd348f4c9df312ca6f9 – < a59edda6eda1252340354322d8ab318b2e9052fb
- affected d15662682db232da77136cd348f4c9df312ca6f9 – < 9b22f13524fa0de0d963bbd3002df6c28bae3395
- affected d15662682db232da77136cd348f4c9df312ca6f9 – < 4ff9548d84945d2cbf9e4c207288063a200ea397
- affected 5.2
- unaffected < 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.*
- unaffected 6.12.104 – ≤ 6.12.*
- unaffected 6.18.45 – ≤ 6.18.*
- unaffected 7.1.9 – ≤ 7.1.*
- unaffected 7.2 – ≤ *
References
References8
- https://git.kernel.org/stable/c/57195f0ab5cfbb5ee0864e5aff15ceb48f5a5e28 (opens in a new tab)
- https://git.kernel.org/stable/c/0f0ca602941d0a81ae9514943ca06c55159c6385 (opens in a new tab)
- https://git.kernel.org/stable/c/5307a53599fa762c06e475ee4a375252074fd324 (opens in a new tab)
- https://git.kernel.org/stable/c/7f80ad373ce4a7af5367ff273cea0f16e91387f3 (opens in a new tab)
- https://git.kernel.org/stable/c/4a5dfbae5179f6574695012a980476254df2d295 (opens in a new tab)
- https://git.kernel.org/stable/c/a59edda6eda1252340354322d8ab318b2e9052fb (opens in a new tab)
- https://git.kernel.org/stable/c/9b22f13524fa0de0d963bbd3002df6c28bae3395 (opens in a new tab)
- https://git.kernel.org/stable/c/4ff9548d84945d2cbf9e4c207288063a200ea397 (opens in a new tab)
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2026-64594 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2026-74657)Record last updated .