PT-2025-40184 · Linux+3 · Linux Kernel+3

Published 2023-02-23 · Updated 2025-11-24 · CVE-2023-53477

Positive Technologies (AI Summary)

CVSS v3.1

5.5

Medium

Base vector

AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Name of the Vulnerable Software and Affected Versions Linux kernel (affected versions not specified)

Description The Linux kernel contains an issue in the IPv6 implementation related to the calculation of the nexthop length in the rt6 nlmsg size() function. Specifically, when handling lwtunnel encapsulation, the calculation does not correctly account for the encapsulation size of all sibling routes, potentially leading to an incorrect nexthop length. This can trigger a warning in inet6 rt notify(). The issue is reproducible by adding multiple ipvlan interfaces and appending IPv6 routes with encapsulation. The rt6 nh nlmsg size() function is used to correct the calculation by adding the nexthop length of each sibling.

Recommendations At the moment, there is no information about a newer version that contains a fix for this vulnerability.

Exploit

Weakness Enumeration

CWE-131

Related Identifiers

ALSA-2025_16880

BDU:2026-06102

CVE-2023-53477

RHSA-2023:6583

RHSA-2023_6583

SUSE-SU-2025:4189-1

Affected Products

Astra Linux

Linux Kernel

Red Hat

Suse

References · 309

• 🔥 https://github.com/CVEProject/cvelistV5/tree/main/cves/2023/53xxx/CVE-2023-53477.json · Exploit
• https://nvd.nist.gov/vuln/detail/CVE-2023-53477 · Security Note
• https://git.kernel.org/stable/c/aa75d826c221e8d48607aef33836cf872a159cf1 · Patch
• https://security-tracker.debian.org/tracker/CVE-2023-53477 · Vendor Advisory
• https://git.kernel.org/stable/c/e11e4d524eba2d3c8fdf897d7ce3853f7573bae9 · Patch
• https://osv.dev/vulnerability/CVE-2023-53477 · Vendor Advisory
• https://osv.dev/vulnerability/UBUNTU-CVE-2023-53477 · Vendor Advisory
• https://git.kernel.org/stable/c/aba298b35619213ca787d08d472049627d8cd012 · Patch
• https://osv.dev/vulnerability/DEBIAN-CVE-2023-53477 · Vendor Advisory
• https://bdu.fstec.ru/vul/2026-06102 · Security Note
• https://cve.org/CVERecord?id=CVE-2023-53477 · Security Note
• https://osv.dev/vulnerability/BELL-CVE-2023-53477 · Vendor Advisory
• https://git.kernel.org/stable/c/4cc59f386991ec9374cb4bc83dbe1c0b5a95033f · Patch
• https://ubuntu.com/security/CVE-2023-53477 · Vendor Advisory
• https://git.kernel.org/stable/c/dcdddb5f490890d058ea1f194d661219e92fe88d · Patch