Use After Free in Linux

CVE-2023-53559

In the Linux kernel, the following vulnerability has been resolved: ip_vti: fix potential slab-use-after-free in decode_session6 When ip_vti device is set to the qdisc of the sfb type, the cb field of the sent skb may be modified during enqueuing. Then, slab-use-after-free may occur when ip_vti device sends IPv6 packets. As commit f855691975bb ("xfrm6: Fix the nexthdr offset in _decode_session6.") showed, xfrm_decode_session was originally intended only for the receive path. IP6CB(skb)->nhoff is not set during transmission. Therefore, set the cb field in the skb to 0 before sending packets.

Vulnerability class: Use-After-Free

Published · last modified .

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.

EPSS exploit prediction

EPSS: 0.001 (3.5th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 3rd percentile — 3.5% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2023-53559: held from 0.001 to 0.001.

EPSS over last 30 days · oldest: 0.001 · newest: 0.001 · change: +0.000

Affected products

  • Linux — versions f855691975bb06373a98711e4cfe2c224244b536, 3.19, 0
  • Linux Kernel — versions 3.19, 6.5

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2023-53559?
CVE-2023-53559 is a high-severity vulnerability in Linux, classified under Use After Free. CVSS score: 7.8/10. Published 2025-10-04.
How severe is CVE-2023-53559?
High severity. CVSS v3 base score is 7.8 out of 10.