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VulnerabilityPublished Updated

CVE-2026-64024: Linux kernel · Race Condition

Affects Linux kernelSource CVE Database V5

0

Not known to be exploited · CVSS 9.4 Critical · fixed in e47f7060eaf60894e3e4d0e3c4fe6e1f2eacfbdd : patch Linux kernel as a priority.

Data as of 26 Oct 2026, 17:16 UTC

CVSS 3.1 base score
9.4Critical
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.3% chance of exploitation in 30 days – higher than 23% 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 can 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 e47f7060eaf60894e3e4d0e3c4fe6e1f2eacfbdd, 8bb6aa419b142dcc2680177ecc39c4c38db7fc16, 4affe063fa56c880cbea8d0bfded0bb80751579d +1
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 19 Jul 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 Linux kernel to e47f7060eaf60894e3e4d0e3c4fe6e1f2eacfbdd, 8bb6aa419b142dcc2680177ecc39c4c38db7fc16, 4affe063fa56c880cbea8d0bfded0bb80751579d or 1bbf0ced1d9db73ac7893c2187f3459288603e0d.

Affected software

ProductAffectedFixed in
LinuxLinuxAffected
  • ≥ 41eecbd712b73f0d5dcf1152b9a1c27b1f238028, < e47f7060eaf60894e3e4d0e3c4fe6e1f2eacfbdd
Fixed in
  • e47f7060eaf60894e3e4d0e3c4fe6e1f2eacfbdd
LinuxLinuxAffected
  • ≥ 41eecbd712b73f0d5dcf1152b9a1c27b1f238028, < 8bb6aa419b142dcc2680177ecc39c4c38db7fc16
Fixed in
  • 8bb6aa419b142dcc2680177ecc39c4c38db7fc16
LinuxLinuxAffected
  • ≥ 41eecbd712b73f0d5dcf1152b9a1c27b1f238028, < 4affe063fa56c880cbea8d0bfded0bb80751579d
Fixed in
  • 4affe063fa56c880cbea8d0bfded0bb80751579d
LinuxLinuxAffected
  • ≥ 41eecbd712b73f0d5dcf1152b9a1c27b1f238028, < 1bbf0ced1d9db73ac7893c2187f3459288603e0d
Fixed in
  • 1bbf0ced1d9db73ac7893c2187f3459288603e0d
LinuxLinuxAffected
  • =6.10
Fixed in–

Description

In the Linux kernel, the following vulnerability has been resolved: tcp: fix stale per-CPU tcp_tw_isn leak enabling ISN prediction Blamed commit moved the TIME_WAIT-derived ISN from the skb control block to a per-CPU variable, assuming the value would always be consumed by tcp_conn_request() for the same packet that wrote it. That assumption is violated by multiple drop paths between the producer (__this_cpu_write(tcp_tw_isn, isn) in tcp_v{4,6}_rcv()) and the consumer (tcp_conn_request()): - min_ttl / min_hopcount check - xfrm policy check - tcp_inbound_hash() MD5/AO mismatch - tcp_filter() eBPF/SO_ATTACH_FILTER drop - th->syn && th->fin discard in tcp_rcv_state_process() TCP_LISTEN - psp_sk_rx_policy_check() in tcp_v{4,6}_do_rcv() - tcp_checksum_complete() in tcp_v{4,6}_do_rcv() - tcp_v{4,6}_cookie_check() returning NULL When a packet is dropped on any of these paths, tcp_tw_isn is left set. The next SYN processed on the same CPU then consumes the non zero value in tcp_conn_request(), receiving a potentially predictable ISN. This patch moves back tcp_tw_isn to skb->cb[], getting rid of the per-cpu variable. Note that tcp_v{4,6}_fill_cb() do not set it. Very litle impact on overall code size/complexity: $ scripts/bloat-o-meter -t vmlinux.old vmlinux.new add/remove: 0/0 grow/shrink: 2/1 up/down: 8/-15 (-7) Function old new delta tcp_v6_rcv 3038 3042 +4 tcp_v4_rcv 3035 3039 +4 tcp_conn_request 2938 2923 -15 Total: Before=24436060, After=24436053, chg -0.00%

References

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