CVE-2026-64576: Linux kernel · nexthop: initialize extack in nh_res_bucket_migrate()
Affects Linux kernelSource CVE Database V5
Not known to be exploited · CVSS 7.1 High · fixed in eacd2e2117e8682f937967fda1022e7f1c22d91a : patch Linux kernel soon.
Data as of 26 Oct 2026, 13:47 UTC
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 1% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- CISA SSVC
- Exploitation
- No evidence of active exploitation and no public proof of concept
- Automatable
- Attackers cannot reliably automate steps 1–4 of the kill chain
- Technical impact
- Limited control over the software or limited information exposure
CISA SSVC assessment, 2026-10-16.
- Patch
- Available – fixed in eacd2e2117e8682f937967fda1022e7f1c22d91a, d536bf205c71f700f6de2086038c3e1d77724715, c0936c131a71657afc635d0db2ab096d15d473e1 +4
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:HExploitation evidence
Disclosed: evidence found.
CVE published 5 Aug 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
Upgrade to a fixed release listed under Affected software.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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Description
In the Linux kernel, the following vulnerability has been resolved: nexthop: initialize extack in nh_res_bucket_migrate() nh_res_bucket_migrate() passes an uninitialized netlink_ext_ack to call_nexthop_res_bucket_notifiers(). When nh_notifier_res_bucket_info_init() fails (e.g. the kzalloc returns -ENOMEM), the error is propagated back before any notifier sets extack._msg, and the error path formats the stale pointer with pr_err_ratelimited("%s\n", extack._msg). With CONFIG_INIT_STACK_NONE this dereferences uninitialized stack memory: Oops: general protection fault, probably for non-canonical address ... KASAN: maybe wild-memory-access in range [...] RIP: 0010:string (lib/vsprintf.c:730) vsnprintf (lib/vsprintf.c:2945) _printk (kernel/printk/printk.c:2504) nh_res_bucket_migrate (net/ipv4/nexthop.c:1816) nh_res_table_upkeep (net/ipv4/nexthop.c:1866) rtm_new_nexthop (net/ipv4/nexthop.c:3323) rtnetlink_rcv_msg (net/core/rtnetlink.c:7076) netlink_sendmsg (net/netlink/af_netlink.c:1900) Kernel panic - not syncing: Fatal exception Zero-initialize extack so _msg is NULL on error paths that never set it.
References
- git.kernel.org/stable/c/eacd2e2117e8682f937967fda1022e7f1c22d91a (opens in a new tab)
- git.kernel.org/stable/c/37bbd7e1d8df0bec3d187e961783e20c30533d2c (opens in a new tab)
- git.kernel.org/stable/c/c0936c131a71657afc635d0db2ab096d15d473e1 (opens in a new tab)
- git.kernel.org/stable/c/3081702ea5aca0aeed9c1ade8eadf6cde8db6b7d (opens in a new tab)
- git.kernel.org/stable/c/d536bf205c71f700f6de2086038c3e1d77724715 (opens in a new tab)
- git.kernel.org/stable/c/18506d7263768d76ac8e057ba55a4d9da50aad66 (opens in a new tab)
- git.kernel.org/stable/c/6347c5314cee49f364aaf2e40ff15415a57a116e (opens in a new tab)