Answer in brief
CVE-2026-74598 records a High severity (CVSS 7.5) vulnerability in ipv6: fix Route Information option length validation. The current sources do not mark it as known exploited. The current feed maps 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.
CVSS is 7.5. 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). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| Linux/Linuxgeneric | >=70ceb4f53929f73746be72f73707cd9f8753e2fc <2f6f94eda12430fb41b24b44a71e2ea4e93561d7 || >=70ceb4f53929f73746be72f73707cd9f8753e2fc <7eac87396c44a312be457ef41d4c5687883be9a2 || >=70ceb4f53929f73746be72f73707cd9f8753e2fc <7309529f257ae18e72112ef9f614edfd6df229bb || >=70ceb4f53929f73746be72f73707cd9f8753e2fc <0b9e02f3bd31c888f2ccdc0ca08e546d6abe9c4d || >=70ceb4f53929f73746be72f73707cd9f8753e2fc <ff3cb05289b8a4ef95fa7ea14c7d34818359edbb || >=70ceb4f53929f73746be72f73707cd9f8753e2fc <3b2231e358d26e3aec5d8040b1fb777af03c5f05 || >=70ceb4f53929f73746be72f73707cd9f8753e2fc <da64ed1f346ba84df574d6469fa2e422b2511719 || >=70ceb4f53929f73746be72f73707cd9f8753e2fc <d1ad8fb2ac6a1afb71dc22d9ae8efb4dda96c824 | 2f6f94eda12430fb41b24b44a71e2ea4e93561d7, 7eac87396c44a312be457ef41d4c5687883be9a2, 7309529f257ae18e72112ef9f614edfd6df229bb, 0b9e02f3bd31c888f2ccdc0ca08e546d6abe9c4d, ff3cb05289b8a4ef95fa7ea14c7d34818359edbb, 3b2231e358d26e3aec5d8040b1fb777af03c5f05, da64ed1f346ba84df574d6469fa2e422b2511719, d1ad8fb2ac6a1afb71dc22d9ae8efb4dda96c824 |
| Linux/Linuxgeneric | 2.6.17 | Not reported |
Published upstream
Aug 22, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Aug 25, 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: ipv6: fix Route Information option length validation rt6_route_rcv() validates the Route Information option (RFC 4191) length against the prefix length, but both checks are off by one. rinfo->length is the ND option length in units of 8 octets and it *includes* the 8-byte option header, so an option carrying N bytes of prefix has length == 1 + N/8. RFC 4191 section 2.3 requires length 3 when Prefix Length is greater than 64, and 2 or 3 when it is greater than 0. The code accepts length >= 2 and length >= 1 respectively. ipv6_addr_prefix() then copies prefix_len/8 bytes out of rinfo->prefix, so a Router Advertisement with (prefix_len=128, length=2) or (prefix_len=64, length=1) makes the kernel read up to 8 bytes past the end of the option. Those bytes end up in the prefix of the route that gets installed, so they are visible to userspace: # RA with a Route Information option (prefix_len=128, length=2) # followed by a source link-layer address option, 01 01 de ad be ef ca fe $ ip -6 route show 2001:db8:dead:beef:101:dead:beef:cafe via fe80::1234 dev veth0 proto ra ^^^^^^^^^^^^^^^^^^ the next option, read out of bounds When the Route Information option is the last one in the packet, those eight bytes come from the skb tail room instead. Reject the option lengths RFC 4191 does not allow.
Quoted source text, attributed separately from HOL analysis.