What is CVE-2025-39963?

CVE-2025-39963 is a high-severity vulnerability in Linux, classified under Missing Release of Memory after Effective Lifetime. CVSS score: 7.8/10. Published 2025-10-09.

How severe is CVE-2025-39963?

High severity. CVSS v3 base score is 7.8 out of 10.

Is CVE-2025-39963 known to be exploited?

1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.

Vulnerability in Linux

CVE-2025-39963

In the Linux kernel, the following vulnerability has been resolved: io_uring: fix incorrect io_kiocb reference in io_link_skb In io_link_skb function, there is a bug where prev_notif is incorrectly assigned using 'nd' instead of 'prev_nd'. This causes the context validation check to compare the current notification with itself instead of comparing it with the previous notification. Fix by using the correct prev_nd parameter when obtaining prev_notif.

EPSS: 0.001 (3.8th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 7.8 (High). Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.

Affected products

Linux — versions 6fe4220912d19152a26ce19713ab232f4263018d, 6.10, 0
Linux Linux_kernel — versions 6.17

Weakness classification (CWE)

CWE-401 — Missing Release of Memory after Effective Lifetime

Public proof-of-concept exploits

fkie-cad/nvd-json-data-feeds

References

416baaa9-dc9f-4396-8d5f-8c081fb06d67 (Patch)
416baaa9-dc9f-4396-8d5f-8c081fb06d67 (Patch)
416baaa9-dc9f-4396-8d5f-8c081fb06d67 (Patch)

Frequently asked questions

What is CVE-2025-39963?: CVE-2025-39963 is a high-severity vulnerability in Linux, classified under Missing Release of Memory after Effective Lifetime. CVSS score: 7.8/10. Published 2025-10-09.
How severe is CVE-2025-39963?: High severity. CVSS v3 base score is 7.8 out of 10.
Is CVE-2025-39963 known to be exploited?: 1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.