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CVE-2026-97903 high CVSS 7.8

Vulnerability in Linux kernel (CVE-2026-97903)

Summary

Vulnerability in Linux kernel (CVE-2026-97903). 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:

exit: hold a reference to thread_pid across proc_flush_pid

Commit 0a36bad01731 ("release_task: kill the no longer needed
get/put_pid(thread_pid)") removed the reference around proc_flush_pid().
It assumed that free_pids(post.pids) at the end of release_task() would
keep thread_pid alive until then.

That assumption is wrong. __change_pid() only records a detached PID in
post.pids when pid_has_task() is false for every PIDTYPE. If another task
still uses the exiting task's PID as its process group or session ID,
__unhash_process() removes the exiting task's PIDTYPE_PID link but leaves
the PID out of post.pids. release_task() therefore holds no reference to
it after dropping tasklist_lock.

The other task can then remove the remaining PIDTYPE links. Its
free_pids() call schedules delayed_put_pid(), and the RCU callback can free
the PID before the first release_task() reaches proc_flush_pid().

An unprivileged reproducer races wait4(-1) against setsid() to trigger this
ordering. Three of three fresh v7.2 KASAN boots reported:

BUG: KASAN: slab-use-after-free in
proc_invalidate_siblings_dcache+0x3e2/0x3f0
Read of size 8 by task h7_pid_reaper/1921

Call Trace:
 proc_invalidate_siblings_dcache
 release_task
 wait_consider_task
 __do_wait
 do_wait
 kernel_wait4

Freed by task 0:
 kmem_cache_free
 put_pid
 delayed_put_pid
 rcu_core

Last potential…

Source: NIST National Vulnerability Database NVD GitHub Advisory

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-2026-97903 has been found in Linux kernel.
Successful exploitation can lead to full system takeover. CVSS score: 7.8/10.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "Linux kernel CVE-2026-97903" on the vendor's site.

CVE-2026-97903 (Linux kernel) — CVSS v3 7.8
Attack vector: local / 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.

❓ What is the problem

A vulnerability (unclassified) exists in Linux kernel.

📍 Affected scope

Check the vendor advisory for the affected versions of Linux kernel.

🔥 Severity

Severity: High (CVSS 7.8/10). Successful exploitation can lead to full system takeover.

🔧 How to fix

Update to the patched release per vendor advisory.

🛡️ Workaround

Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.

🔍 Detection

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

  1. 1
    Identify 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。

  2. 2
    Post-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

Linux Kernel
[{"type":"ECOSYSTEM","events":[{"introduced":"6.16.0"},{"fixed":"6.18.53"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"7.2.7"}]}]

Fix status by distribution

Fixed packages published by each distribution for this CVE

References

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