Answer in brief
CVE-2026-64542 records a Unknown severity vulnerability in ipv6: ndisc: fix NULL deref in accept_untracked_na(). 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.
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). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| Linux/Linuxgeneric | >=aaa5f515b16b6b3e137779ffb4c9558bb58c1e75 <160d3f0d7a556ceae505dcab521a37057b4ce28f || >=aaa5f515b16b6b3e137779ffb4c9558bb58c1e75 <62c719203cb521b64fab74da94a81bdde5c18808 || >=aaa5f515b16b6b3e137779ffb4c9558bb58c1e75 <a6450f7cfae57b382cbaf66a577765c9a88b3c58 || >=aaa5f515b16b6b3e137779ffb4c9558bb58c1e75 <63d1c23764de2309cedbb779c75188d257a09d9b || >=aaa5f515b16b6b3e137779ffb4c9558bb58c1e75 <d186e942365acece7c56d39da05dd63bf95b280a | 160d3f0d7a556ceae505dcab521a37057b4ce28f, 62c719203cb521b64fab74da94a81bdde5c18808, a6450f7cfae57b382cbaf66a577765c9a88b3c58, 63d1c23764de2309cedbb779c75188d257a09d9b, d186e942365acece7c56d39da05dd63bf95b280a |
| Linux/Linuxgeneric | 6.0 | Not reported |
Published upstream
Jul 27, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Aug 17, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Aug 3, 2026
In the Linux kernel, the following vulnerability has been resolved: ipv6: ndisc: fix NULL deref in accept_untracked_na() accept_untracked_na() re-fetches the inet6_dev with __in6_dev_get(dev) and dereferences idev->cnf.accept_untracked_na without a NULL check, even though its only caller ndisc_recv_na() already fetched and NULL-checked idev for the same device. Both reads of dev->ip6_ptr run in the same RCU read-side critical section, but a concurrent addrconf_ifdown() can clear dev->ip6_ptr between them: lowering the MTU below IPV6_MIN_MTU calls addrconf_ifdown() without the synchronize_net() that orders the unregister path, so the re-fetch returns NULL and oopses: BUG: KASAN: null-ptr-deref in ndisc_recv_na (net/ipv6/ndisc.c:974) Read of size 4 at addr 0000000000000364 Call Trace: <IRQ> ndisc_recv_na (net/ipv6/ndisc.c:974) icmpv6_rcv (net/ipv6/icmp.c:1193) ip6_protocol_deliver_rcu (net/ipv6/ip6_input.c:479) ip6_input_finish (net/ipv6/ip6_input.c:534) ip6_input (net/ipv6/ip6_input.c:545) ip6_mc_input (net/ipv6/ip6_input.c:635) ipv6_rcv (net/ipv6/ip6_input.c:351) </IRQ> It is reachable by an unprivileged user via a network namespace. Pass the caller's already validated idev instead of re-fetching it; the idev stays alive for the whole RCU critical section, so it is safe even after dev->ip6_ptr has been cleared.
Quoted source text, attributed separately from HOL analysis.
Answer in brief
CVE-2026-64542 records a Unknown severity vulnerability in ipv6: ndisc: fix NULL deref in accept_untracked_na(). 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.
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). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| Linux/Linuxgeneric | >=aaa5f515b16b6b3e137779ffb4c9558bb58c1e75 <160d3f0d7a556ceae505dcab521a37057b4ce28f || >=aaa5f515b16b6b3e137779ffb4c9558bb58c1e75 <62c719203cb521b64fab74da94a81bdde5c18808 || >=aaa5f515b16b6b3e137779ffb4c9558bb58c1e75 <a6450f7cfae57b382cbaf66a577765c9a88b3c58 || >=aaa5f515b16b6b3e137779ffb4c9558bb58c1e75 <63d1c23764de2309cedbb779c75188d257a09d9b || >=aaa5f515b16b6b3e137779ffb4c9558bb58c1e75 <d186e942365acece7c56d39da05dd63bf95b280a | 160d3f0d7a556ceae505dcab521a37057b4ce28f, 62c719203cb521b64fab74da94a81bdde5c18808, a6450f7cfae57b382cbaf66a577765c9a88b3c58, 63d1c23764de2309cedbb779c75188d257a09d9b, d186e942365acece7c56d39da05dd63bf95b280a |
| Linux/Linuxgeneric | 6.0 | Not reported |
Published upstream
Jul 27, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Aug 17, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Aug 3, 2026
In the Linux kernel, the following vulnerability has been resolved: ipv6: ndisc: fix NULL deref in accept_untracked_na() accept_untracked_na() re-fetches the inet6_dev with __in6_dev_get(dev) and dereferences idev->cnf.accept_untracked_na without a NULL check, even though its only caller ndisc_recv_na() already fetched and NULL-checked idev for the same device. Both reads of dev->ip6_ptr run in the same RCU read-side critical section, but a concurrent addrconf_ifdown() can clear dev->ip6_ptr between them: lowering the MTU below IPV6_MIN_MTU calls addrconf_ifdown() without the synchronize_net() that orders the unregister path, so the re-fetch returns NULL and oopses: BUG: KASAN: null-ptr-deref in ndisc_recv_na (net/ipv6/ndisc.c:974) Read of size 4 at addr 0000000000000364 Call Trace: <IRQ> ndisc_recv_na (net/ipv6/ndisc.c:974) icmpv6_rcv (net/ipv6/icmp.c:1193) ip6_protocol_deliver_rcu (net/ipv6/ip6_input.c:479) ip6_input_finish (net/ipv6/ip6_input.c:534) ip6_input (net/ipv6/ip6_input.c:545) ip6_mc_input (net/ipv6/ip6_input.c:635) ipv6_rcv (net/ipv6/ip6_input.c:351) </IRQ> It is reachable by an unprivileged user via a network namespace. Pass the caller's already validated idev instead of re-fetching it; the idev stays alive for the whole RCU critical section, so it is safe even after dev->ip6_ptr has been cleared.
Quoted source text, attributed separately from HOL analysis.