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CVE-2026-64542— ipv6: ndisc: fix NULL deref in accept_untracked_na()

Quick assessment

Affected
Linux Linux
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

Linux kernel是美国Linux基金会开源的一款操作系统内核。 Linux kernel存在安全漏洞，该漏洞源于accept_untracked_na()函数中重新获取inet6_dev时未进行空指针检查，可能导致空指针取消引用。

AI Predicted 6.5 Difficulty: Moderate EPSS 0.17% · P6

Affected Version Matrix 14

VendorProduct Version RangeStatus
Linux Linux aaa5f515b16b6b3e137779ffb4c9558bb58c1e75< e5ba3017e46f275ad347e762e8eecacec5efa41d affected
aaa5f515b16b6b3e137779ffb4c9558bb58c1e75< 160d3f0d7a556ceae505dcab521a37057b4ce28f affected
aaa5f515b16b6b3e137779ffb4c9558bb58c1e75< 62c719203cb521b64fab74da94a81bdde5c18808 affected
aaa5f515b16b6b3e137779ffb4c9558bb58c1e75< a6450f7cfae57b382cbaf66a577765c9a88b3c58 affected
aaa5f515b16b6b3e137779ffb4c9558bb58c1e75< 63d1c23764de2309cedbb779c75188d257a09d9b affected
aaa5f515b16b6b3e137779ffb4c9558bb58c1e75< d186e942365acece7c56d39da05dd63bf95b280a affected
6.0 affected
< 6.0 unaffected
… +6 more rows
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I. Basic Information for CVE-2026-64542

Vulnerability Information
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Vulnerability Title
ipv6: ndisc: fix NULL deref in accept_untracked_na()
Source: CVE Program / CVE List V5
Vulnerability Description
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.
Source: CVE Program / CVE List V5
CVSS Information
N/A
Source: CVE Program / CVE List V5
Vulnerability Type
N/A
Source: CVE Program / CVE List V5
Vulnerability Title
Linux kernel 安全漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
Linux kernel是美国Linux基金会开源的一款操作系统内核。 Linux kernel存在安全漏洞，该漏洞源于accept_untracked_na()函数中重新获取inet6_dev时未进行空指针检查，可能导致空指针取消引用。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

Vendor Product Affected Versions CPE Subscribe
Linux Linux aaa5f515b16b6b3e137779ffb4c9558bb58c1e75 ~ e5ba3017e46f275ad347e762e8eecacec5efa41d -
Linux Linux 6.0 -

II. Public POCs for CVE-2026-64542

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III. Intelligence Information for CVE-2026-64542

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Patches & Fixes for CVE-2026-64542 (6)

Same Patch Batch · Linux · 2026-07-27 · 26 CVEs total

CVE-2026-64534 9.8 CRITICAL nvmet-tcp: check INIT_FAILED before nvmet_req_uninit in digest error path
CVE-2026-64535 9.8 CRITICAL nvmet-tcp: Fix potential UAF when ddgst mismatch
CVE-2026-64541 9.8 CRITICAL net/smc: fix UAF in smc_cdc_rx_handler() by pinning the socket
CVE-2026-64551 9.1 CRITICAL sctp: validate STALE_COOKIE cause length before reading staleness
CVE-2026-64555 8.8 HIGH KVM: arm64: nv: Fix SPSR_EL2 restore in kvm_hyp_handle_mops()
CVE-2026-64554 8.8 HIGH netfilter: bridge: fix stale prevhdr pointer in br_ip6_fragment()
CVE-2026-64552 8.4 HIGH virtio-net: fix len check in receive_big()
CVE-2026-64548 8.4 HIGH bpf, sockmap: reject overflowing copy + len in bpf_msg_push_data()
CVE-2026-64536 8.1 HIGH staging: rtl8723bs: fix OOB reads in is_ap_in_tkip() IE loop
CVE-2026-64547 8.1 HIGH net: usb: net1080: validate packet_len before pad-byte access in rx_fixup
CVE-2026-64540 8.1 HIGH usbnet: gl620a: fix out-of-bounds read in genelink_rx_fixup()
CVE-2026-64532 7.8 HIGH fs/ntfs3: bound NTFS_DE view.data_off in UpdateRecordData{Root,Allocation}
CVE-2026-64543 7.8 HIGH tipc: fix use-after-free of the discoverer in tipc_disc_rcv()
CVE-2026-64539 7.8 HIGH Bluetooth: eir: Fix stack OOB write when prepending the Flags AD
CVE-2026-17523 7.8 HIGH can: bcm: switch timer to HRTIMER_MODE_SOFT and remove hrtimer_tasklet
CVE-2026-64533 7.8 HIGH fs/ntfs3: validate lcns_follow in log_replay conversion
CVE-2026-64531 7.8 HIGH net: openvswitch: reject oversized nested action attrs
CVE-2026-64545 7.5 HIGH net, bpf: check master for NULL in xdp_master_redirect()
CVE-2026-64550 7.3 HIGH net: qualcomm: rmnet: validate MAP frame length before ingress parsing
CVE-2026-64546 7.1 HIGH drm/edid: fix OOB read in drm_parse_tiled_block()

Showing top 20 of 26 CVEs. View all on vendor page &rarr; →

IV. Related Vulnerabilities

Same product: Linux
Same vendor: Linux

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