Use-After-Free in Linux kernel (CVE-2024-50154)
Summary
Vulnerability in Linux kernel (CVE-2024-50154). Successful exploitation can lead to full system takeover.
Original description
The description as published by the source.
In the Linux kernel, the following vulnerability has been resolved:
tcp/dccp: Don't use timer_pending() in reqsk_queue_unlink().
Martin KaFai Lau reported use-after-free [0] in reqsk_timer_handler().
"""
We are seeing a use-after-free from a bpf prog attached to
trace_tcp_retransmit_synack. The program passes the req->sk to the
bpf_sk_storage_get_tracing kernel helper which does check for null
before using it.
"""
The commit 83fccfc3940c ("inet: fix potential deadlock in
reqsk_queue_unlink()") added timer_pending() in reqsk_queue_unlink() not
to call del_timer_sync() from reqsk_timer_handler(), but it introduced a
small race window.
Before the timer is called, expire_timers() calls detach_timer(timer, true)
to clear timer->entry.pprev and marks it as not pending.
If reqsk_queue_unlink() checks timer_pending() just after expire_timers()
calls detach_timer(), TCP will miss del_timer_sync(); the reqsk timer will
continue running and send multiple SYN+ACKs until it expires.
The reported UAF could happen if req->sk is close()d earlier than the timer
expiration, which is 63s by default.
The scenario would be
-
inet_csk_complete_hashdance() calls inet_csk_reqsk_queue_drop(),
but del_timer_sync() is missed -
reqsk timer is executed and scheduled again
-
req->sk is accept()ed and reqsk_put() decrements rsk_refcnt, but
reqsk timer still has another one, and inet_csk_accept() does not
clear req->sk for non-TFO sockets -
sk is close()d…
Source: NIST National Vulnerability Database NVD
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2024-50154 has been found in Linux kernel.
Successful exploitation can lead to full system takeover. CVSS score: 9.8/10.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "Linux kernel CVE-2024-50154" on the vendor's site.
CVE-2024-50154 (Linux kernel) — CWE-416 / CVSS v3 9.8
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
Use-after-free (CWE-416) exists in Linux kernel.
Check the vendor advisory for the affected versions of Linux kernel.
Severity: Critical (CVSS 9.8/10). Successful exploitation can lead to full system takeover.
Update to the patched release per vendor advisory.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Audit SBOM/dependencies to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
-
1Identify exposure identify
Audit SBOM/dependencies for affected components.資産台帳・SBOM・依存マニフェストで Linux kernel を使っているサービスとバージョンを洗い出す。
-
2Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。
Affected packages
Fix status by distribution
Fixed packages published by each distribution for this CVE
- Debian DEBIAN-CVE-2024-50154 linux Fixed in: 5.10.237-1
- Ubuntu UBUNTU-CVE-2024-50154 linux-aws
References
- advisory github.com
- advisory nvd.nist.gov
- package git.kernel.org
- web git.kernel.org
- web git.kernel.org
- web git.kernel.org
- web git.kernel.org
- web git.kernel.org
- web git.kernel.org
- web git.kernel.org
- web lists.debian.org
- web lists.debian.org