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Vulnerabilities

Vulnerability · CVE-2025-40257

In the Linux kernel, the following vulnerability has been resolved: mptcp: fix a race in mptcp_pm_del_add_timer() mptcp_pm_del_add_timer() can call sk_stop_timer_sync(sk, &entry->a

Published Dec 4, 2025 · catalog updated Aug 5, 2026 · Linux Linux

Last checked Oct 26, 2026. A connected source was read within the last 7 days.

Check if you run it

No confirmed exploitation is on record for CVE-2025-40257. EPSS is 0.46%. Act only if a listed version of Linux Linux is installed.

Gaps on this record

  • No vendor fix or required action is stored. Compare the linked advisory before you change production.

Same product and reporting

Severity
Critical9.8
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.46%
Remediation
Version ranges on file
Affected products
vendor Linux Linux 00cfd77b9063dcdf3628a7087faba60de85a9cc8 <426358d9be7ce3518966422f87b96f1bad27295f

In the Linux kernel, the following vulnerability has been resolved: mptcp: fix a race in mptcp_pm_del_add_timer() mptcp_pm_del_add_timer() can call sk_stop_timer_sync(sk, &entry->add_timer) while another might have free entry already, as reported by syzbot. Add RCU protection to fix this issue. Also change confusing add_timer variable with stop_timer boolean. syzbot report: BUG: KASAN: slab-use-after-free in __timer_delete_sync+0x372/0x3f0 kernel/time/timer.c:1616 Read of size 4 at addr ffff8880311e4150 by task kworker/1:1/44 CPU: 1 UID: 0 PID: 44 Comm: kworker/1:1 Not tainted syzkaller #0 PRE

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • vendor Linux Linux 00cfd77b9063dcdf3628a7087faba60de85a9cc8 <426358d9be7ce3518966422f87b96f1bad27295f00cfd77b9063dcdf3628a7087faba60de85a9cc8 <426358d9be7ce3518966422f87b96f1bad27295f

How to fix CVE-2025-40257

  • Upgrade

    CVE-2025-40257 lists a fix boundary at 426358d9be7ce3518966422f87b96f1bad27295f. Compare the installed build with that boundary before you change production.

  • Version check

    Seen in 00cfd77b9063dcdf3628a7087faba60de85a9cc8 <426358d9be7ce3518966422f87b96f1bad27295f

  • Advisory

    Open the cve_org record and follow its fix.

  • Official advisories

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2025-40257. EPSS is 0.46%. Act only if a listed version of Linux Linux is installed.

Which versions are affected?

Compare what you have installed with Linux Linux 00cfd77b9063dcdf3628a7087faba60de85a9cc8 <426358d9be7ce3518966422f87b96f1bad27295f 00cfd77b9063dcdf3628a7087faba60de85a9cc8 <426358d9be7ce3518966422f87b96f1bad27295f. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

No weakness class is stored. EPSS 0.46%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Dec 4, 2025 · EUVD

    Detected

    In the Linux kernel, the following vulnerability has been resolved: mptcp: fix a race in mptcp_pm_del_add_timer() mptcp_pm_del_add_timer() can call sk_stop_timer_sync(sk, &entry->add_timer) while another might have free entry already, as reported by syzbot. Add RCU protection to fix this issue. Also change confusing add_timer variable with stop_timer boolean. syzbot report: BUG: KASAN: slab-use-af

  2. Aug 5, 2026 · EUVD

    Updated

    In the Linux kernel, the following vulnerability has been resolved: mptcp: fix a race in mptcp_pm_del_add_timer() mptcp_pm_del_add_timer() can call sk_stop_timer_sync(sk, &entry->add_timer) while another might have free entry already, as reported by syzbot. Add RCU protection to fix this issue. Also change confusing add_timer variable with stop_timer boolean. syzbot report: BUG: KASAN: slab-use-af

Sources

  • CVE.orgVulnerability recordCVE-2025-40257

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2025-40257

    30-day exploitation probability 0.46%

    first.org
  • EUVDVulnerability recordEUVD-2025-201200

    In the Linux kernel, the following vulnerability has been resolved: mptcp: fix a race in mptcp_pm_del_add_timer() mptcp_pm_del_add_timer() can call sk_stop_timer_sync(sk, &entry->add_timer) while another might have free entry already, as reported by syzbot. Add RCU protection to

    euvd.enisa.europa.eu

References

Freshness

Last verified in this catalog Oct 26, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.

  • FIRST EPSSOct 26, 2026
  • CVE.orgOct 26, 2026
  • EUVDOct 26, 2026