Answer in brief
CVE-2026-99042 records a High severity (CVSS 8.4) vulnerability in io_uring/net: populate CONNECT filter fields for 24-byte sockaddr_in6. 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 8.4. 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 | >=899bea8248cee35d54760a5e7d61a76af8e64411 <596a955d2d01b7e29d9fed60ebcf7c4ba518b8e5 || >=899bea8248cee35d54760a5e7d61a76af8e64411 <aa5d5f8e502318e783545ba5d04bb40130b83e20 | 596a955d2d01b7e29d9fed60ebcf7c4ba518b8e5, aa5d5f8e502318e783545ba5d04bb40130b83e20 |
| Linux/Linuxgeneric | 7.2 | Not reported |
Published upstream
Oct 23, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Oct 24, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Oct 23, 2026
In the Linux kernel, the following vulnerability has been resolved: io_uring/net: populate CONNECT filter fields for 24-byte sockaddr_in6 io_connect_bpf_populate() fills connect.port and connect.v6_addr for AF_INET6 only when addr_len >= sizeof(struct sockaddr_in6), i.e. 28 bytes. The IPv6 connect paths accept SIN6_LEN_RFC2133 (24 bytes), which already holds sin6_port and sin6_addr. io_connect() passes addr_len to the socket layer unchanged. At addr_len 24 the filter sees family AF_INET6 with port and address zero, while the kernel connects to the real destination. A filter that denies an IPv6 port or address is bypassed. Denying connect.port == P rejects [::1]:P with -EACCES at addr_len 28 but connects at addr_len 24. Use SIN6_LEN_RFC2133 as the threshold. sin6_scope_id stays zero when absent. The threshold mismatch was found by an AI coding assistant (Claude Code) comparing this hook against the net/ipv6 length checks on my instructions; it also drafted the reproducer and this patch. I verified the bypass and the fix in a VM on 7.3-rc6 and that 7.2 has the same code.
Quoted source text, attributed separately from HOL analysis.