Answer in brief
CVE-2026-74657 records a Unknown severity vulnerability in ipv4: Fix fib_nlmsg_size() for RTA_VIA nexthops. The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic), Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
A CVSS score is not reported in the current record. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps Linux/Linux (generic), Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| Linux/Linuxgeneric | >=d15662682db232da77136cd348f4c9df312ca6f9 <0f0ca602941d0a81ae9514943ca06c55159c6385 || >=d15662682db232da77136cd348f4c9df312ca6f9 <5307a53599fa762c06e475ee4a375252074fd324 || >=d15662682db232da77136cd348f4c9df312ca6f9 <7f80ad373ce4a7af5367ff273cea0f16e91387f3 || >=d15662682db232da77136cd348f4c9df312ca6f9 <4a5dfbae5179f6574695012a980476254df2d295 || >=d15662682db232da77136cd348f4c9df312ca6f9 <a59edda6eda1252340354322d8ab318b2e9052fb || >=d15662682db232da77136cd348f4c9df312ca6f9 <9b22f13524fa0de0d963bbd3002df6c28bae3395 || >=d15662682db232da77136cd348f4c9df312ca6f9 <4ff9548d84945d2cbf9e4c207288063a200ea397 | 0f0ca602941d0a81ae9514943ca06c55159c6385, 5307a53599fa762c06e475ee4a375252074fd324, 7f80ad373ce4a7af5367ff273cea0f16e91387f3, 4a5dfbae5179f6574695012a980476254df2d295, a59edda6eda1252340354322d8ab318b2e9052fb, 9b22f13524fa0de0d963bbd3002df6c28bae3395, 4ff9548d84945d2cbf9e4c207288063a200ea397 |
| Linux/Linuxgeneric | 5.2 | Not reported |
| Linux/Linuxgeneric | >=d15662682db232da77136cd348f4c9df312ca6f9 <57195f0ab5cfbb5ee0864e5aff15ceb48f5a5e28 || >=d15662682db232da77136cd348f4c9df312ca6f9 <0f0ca602941d0a81ae9514943ca06c55159c6385 || >=d15662682db232da77136cd348f4c9df312ca6f9 <5307a53599fa762c06e475ee4a375252074fd324 || >=d15662682db232da77136cd348f4c9df312ca6f9 <7f80ad373ce4a7af5367ff273cea0f16e91387f3 || >=d15662682db232da77136cd348f4c9df312ca6f9 <4a5dfbae5179f6574695012a980476254df2d295 || >=d15662682db232da77136cd348f4c9df312ca6f9 <a59edda6eda1252340354322d8ab318b2e9052fb || >=d15662682db232da77136cd348f4c9df312ca6f9 <9b22f13524fa0de0d963bbd3002df6c28bae3395 || >=d15662682db232da77136cd348f4c9df312ca6f9 <4ff9548d84945d2cbf9e4c207288063a200ea397 | 57195f0ab5cfbb5ee0864e5aff15ceb48f5a5e28, 0f0ca602941d0a81ae9514943ca06c55159c6385, 5307a53599fa762c06e475ee4a375252074fd324, 7f80ad373ce4a7af5367ff273cea0f16e91387f3, 4a5dfbae5179f6574695012a980476254df2d295, a59edda6eda1252340354322d8ab318b2e9052fb, 9b22f13524fa0de0d963bbd3002df6c28bae3395, 4ff9548d84945d2cbf9e4c207288063a200ea397 |
Published upstream
Aug 22, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Aug 27, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Aug 22, 2026
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.
Quoted source text, attributed separately from HOL analysis.