What’s Vulnerable › Vulnerabilities

CVE-2024-53206: tcp: Fix use-after-free of nreq in reqsk_timer_handler().

• Severity: high (CVSS 7.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.6% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2024-12-27 · updated 2026-08-04
• Weakness: CWE-416

Description

In the Linux kernel, the following vulnerability has been resolved: tcp: Fix use-after-free of nreq in reqsk_timer_handler(). The cited commit replaced inet_csk_reqsk_queue_drop_and_put() with __inet_csk_reqsk_queue_drop() and reqsk_put() in reqsk_timer_handler(). Then, oreq should be passed to reqsk_put() instead of req; otherwise use-after-free of nreq could happen when reqsk is migrated but the retry attempt failed (e.g. due to timeout). Let's pass oreq to reqsk_put().

Affected products

• Linux kernel: from 5.15.170 before 5.15.174; from 6.1.115 before 6.1.120; from 6.6.59 before 6.6.64; from 6.11.6 before 6.11.11; from 6.12 before 6.12.2 — fixed in 5.15.174, 6.1.120, 6.11.11, 6.12.2, 6.6.64

How to fix

Upgrade to a fixed version: Linux kernel 5.15.174, 6.1.120, 6.11.11, 6.12.2. Check the vendor advisory for mitigations.

References

• https://git.kernel.org/stable/c/2dcc86fefe09ac853158afd96b60d544af115dc5
• https://git.kernel.org/stable/c/65ed89cad1f57034c256b016e89e8c0a4ec7c65b
• https://git.kernel.org/stable/c/6d845028609a4af0ad66f499ee0bd5789122b067
• https://git.kernel.org/stable/c/9a3c1ad93e6fba67b3a637cfa95a57a6685e4908
• https://git.kernel.org/stable/c/c31e72d021db2714df03df6c42855a1db592716c
• https://git.kernel.org/stable/c/d0eb14cb8c08b00c36a3d5dc57a6f428b301f721
• https://lists.debian.org/debian-lts-announce/2025/03/msg00001.html

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