CVE-2026-64542 Affecting kernel-azure-vdso package, versions <6.12.0-160000.38.1


Severity

Recommended
0.0
medium
0
10

Based on SUSE Linux Enterprise Server security rating.

Threat Intelligence

EPSS
0.17% (6th percentile)

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  • Snyk IDSNYK-SLES1600-KERNELAZUREVDSO-20319706
  • published30 Sept 2026
  • disclosed22 Sept 2026

Introduced: 22 Sep 2026

NewCVE-2026-64542  (opens in a new tab)

How to fix?

Upgrade SLES:16.0.0 kernel-azure-vdso to version 6.12.0-160000.38.1 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel-azure-vdso package and not the kernel-azure-vdso package as distributed by SLES. See How to fix? for SLES:16.0.0 relevant fixed versions and status.

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.

CVSS Base Scores

version 3.1