ipv4: Fix fib_nlmsg_size() for RTA_VIA nexthops
Summary
| CVE | CVE-2026-74657 |
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| State | PUBLISHED |
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| Assigner | Linux |
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| Source Priority | CVE Program / NVD first with legacy fallback |
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| Published | 2026-08-22 16:16:39 UTC |
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| Updated | 2026-08-22 16:16:39 UTC |
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| 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. |
|---|
Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|
| CNA |
Linux |
Linux |
affected d15662682db232da77136cd348f4c9df312ca6f9 0f0ca602941d0a81ae9514943ca06c55159c6385 git |
Not specified |
| CNA |
Linux |
Linux |
affected d15662682db232da77136cd348f4c9df312ca6f9 5307a53599fa762c06e475ee4a375252074fd324 git |
Not specified |
| CNA |
Linux |
Linux |
affected d15662682db232da77136cd348f4c9df312ca6f9 7f80ad373ce4a7af5367ff273cea0f16e91387f3 git |
Not specified |
| CNA |
Linux |
Linux |
affected d15662682db232da77136cd348f4c9df312ca6f9 4a5dfbae5179f6574695012a980476254df2d295 git |
Not specified |
| CNA |
Linux |
Linux |
affected d15662682db232da77136cd348f4c9df312ca6f9 a59edda6eda1252340354322d8ab318b2e9052fb git |
Not specified |
| CNA |
Linux |
Linux |
affected d15662682db232da77136cd348f4c9df312ca6f9 9b22f13524fa0de0d963bbd3002df6c28bae3395 git |
Not specified |
| CNA |
Linux |
Linux |
affected d15662682db232da77136cd348f4c9df312ca6f9 4ff9548d84945d2cbf9e4c207288063a200ea397 git |
Not specified |
| CNA |
Linux |
Linux |
affected 5.2 |
Not specified |
| CNA |
Linux |
Linux |
unaffected 5.2 semver |
Not specified |
| CNA |
Linux |
Linux |
unaffected 5.15.216 5.15.* semver |
Not specified |
| CNA |
Linux |
Linux |
unaffected 6.1.183 6.1.* semver |
Not specified |
| CNA |
Linux |
Linux |
unaffected 6.6.152 6.6.* semver |
Not specified |
| CNA |
Linux |
Linux |
unaffected 6.12.104 6.12.* semver |
Not specified |
| CNA |
Linux |
Linux |
unaffected 6.18.45 6.18.* semver |
Not specified |
| CNA |
Linux |
Linux |
unaffected 7.1.9 7.1.* semver |
Not specified |
| CNA |
Linux |
Linux |
unaffected 7.2 * original_commit_for_fix |
Not specified |
References
| Reference | Source | Link | Tags |
|---|
| git.kernel.org/stable/c/4ff9548d84945d2cbf9e4c207288063a200ea397 |
416baaa9-dc9f-4396-8d5f-8c081fb06d67 |
git.kernel.org |
|
| git.kernel.org/stable/c/a59edda6eda1252340354322d8ab318b2e9052fb |
416baaa9-dc9f-4396-8d5f-8c081fb06d67 |
git.kernel.org |
|
| git.kernel.org/stable/c/4a5dfbae5179f6574695012a980476254df2d295 |
416baaa9-dc9f-4396-8d5f-8c081fb06d67 |
git.kernel.org |
|
| git.kernel.org/stable/c/7f80ad373ce4a7af5367ff273cea0f16e91387f3 |
416baaa9-dc9f-4396-8d5f-8c081fb06d67 |
git.kernel.org |
|
| git.kernel.org/stable/c/0f0ca602941d0a81ae9514943ca06c55159c6385 |
416baaa9-dc9f-4396-8d5f-8c081fb06d67 |
git.kernel.org |
|
| git.kernel.org/stable/c/9b22f13524fa0de0d963bbd3002df6c28bae3395 |
416baaa9-dc9f-4396-8d5f-8c081fb06d67 |
git.kernel.org |
|
| git.kernel.org/stable/c/5307a53599fa762c06e475ee4a375252074fd324 |
416baaa9-dc9f-4396-8d5f-8c081fb06d67 |
git.kernel.org |
|
| CVE Program record |
CVE.ORG |
www.cve.org |
canonical |
| NVD vulnerability detail |
NVD |
nvd.nist.gov |
canonical, analysis |
No vendor comments have been submitted for this CVE.
There are currently no legacy QID mappings associated with this CVE.