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VulnerabilityPublished Updated

CVE-2026-64576: Linux kernel · nexthop: initialize extack in nh_res_bucket_migrate()

Affects Linux kernelSource CVE Database V5

0

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

CVSS 3.1 base score
7.1High
How severe the flaw is on the 0–10 CVSS scale.
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:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 5 Aug 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq 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

ProductAffectedFixed in
LinuxLinuxAffected
  • ≥ 7c37c7e00411b3d1e0c5292368317aca69d1f324, < eacd2e2117e8682f937967fda1022e7f1c22d91a
Fixed in
  • eacd2e2117e8682f937967fda1022e7f1c22d91a
LinuxLinuxAffected
  • ≥ 7c37c7e00411b3d1e0c5292368317aca69d1f324, < d536bf205c71f700f6de2086038c3e1d77724715
Fixed in
  • d536bf205c71f700f6de2086038c3e1d77724715
LinuxLinuxAffected
  • ≥ 7c37c7e00411b3d1e0c5292368317aca69d1f324, < c0936c131a71657afc635d0db2ab096d15d473e1
Fixed in
  • c0936c131a71657afc635d0db2ab096d15d473e1
LinuxLinuxAffected
  • ≥ 7c37c7e00411b3d1e0c5292368317aca69d1f324, < 3081702ea5aca0aeed9c1ade8eadf6cde8db6b7d
Fixed in
  • 3081702ea5aca0aeed9c1ade8eadf6cde8db6b7d
LinuxLinuxAffected
  • ≥ 7c37c7e00411b3d1e0c5292368317aca69d1f324, < 18506d7263768d76ac8e057ba55a4d9da50aad66
Fixed in
  • 18506d7263768d76ac8e057ba55a4d9da50aad66
LinuxLinuxAffected
  • ≥ 7c37c7e00411b3d1e0c5292368317aca69d1f324, < 6347c5314cee49f364aaf2e40ff15415a57a116e
Fixed in
  • 6347c5314cee49f364aaf2e40ff15415a57a116e

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

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