How severe is CVE-2026-46259?

CVE-2026-46259 has a CVSS score of 7.8/10, rated HIGH. Immediate patching is strongly recommended.

Which products are affected by CVE-2026-46259?

Affected package information for CVE-2026-46259 is not yet fully mapped. Check the official advisory links for details.

How do I patch CVE-2026-46259?

Apply the linux linux kernel security patch or hotfix for CVE-2026-46259 on the affected version, following the vendor advisory for your exact build.

How do I detect CVE-2026-46259 across my infrastructure?

Inventory every linux linux kernel deployment and check each version against the affected-products list above. Because the exploit targets the running system rather than your application code, also watch for exploitation at the network and runtime layer — O3 flags the exploit behaviour from runtime telemetry and egress traffic even before a vulnerable build is confirmed.

How do I mitigate CVE-2026-46259 if there is no patch (or I can't update yet)?

Cut exposure now: restrict the management/admin interface to trusted networks, segment the device, and apply the vendor's recommended configuration mitigations and any WAF/IPS signature. O3's runtime protection blocks the exploit chain at execution, holding the line on unpatched or end-of-life systems until you can patch.

How does O3 Security protect against CVE-2026-46259?

O3 detects and blocks CVE-2026-46259 exploitation at runtime: eBPF exploit-chain detection, plus L7 egress monitoring that catches the post-exploitation callback and severs the attacker's outbound channel.

Is CVE-2026-46259 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-46259 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2026-46259?

CVE-2026-46259 has an EPSS (Exploit Prediction Scoring System) score of 0.1%, placing it in the 2th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

Which products and versions are affected by CVE-2026-46259?

CVE-2026-46259 affects linux linux kernel. Check the affected-products list on this page against your deployed version to confirm exposure.

When was CVE-2026-46259 published, and has it been updated?

CVE-2026-46259 was published on June 3, 2026 and was last updated on June 17, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

CVE-2026-46259

HIGH

In the Linux kernel, the following vulnerability has been resolved: procfs: fix missing RCU protection when reading real_parent in do_task_stat() When reading /proc/[pid]/stat, do_task_stat()…

Published

Jun 3, 2026

Updated

Jun 17, 2026

Affected

0 pkgs

Patched

None yet

Exploits

None indexed

EPSS Exploitation Probability

via FIRST.org ↗

0.1%probability of exploitation in next 30 days

Lower Risk2th percentile0.00%

EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.

Description

In the Linux kernel, the following vulnerability has been resolved:

procfs: fix missing RCU protection when reading real_parent in do_task_stat()

When reading /proc/[pid]/stat, do_task_stat() accesses task->real_parent without proper RCU protection, which leads to:

cpu 0 cpu 1

do_task_stat var = task->real_parent release_task call_rcu(delayed_put_task_struct) task_tgid_nr_ns(var) rcu_read_lock <--- Too late to protect task->real_parent! task_pid_ptr <--- UAF! rcu_read_unlock

This patch uses task_ppid_nr_ns() instead of task_tgid_nr_ns() to add proper RCU protection for accessing task->real_parent.

Affected Products

1 product · 7 configurations

linux kernellinux

≥ 6.19 && < 6.19.4

range

Detection & mitigation playbook

Vendor / appliance

Detect
Inventory every linux linux kernel deployment and check each version against the affected-products list above. Because the exploit targets the running system rather than your application code, also watch for exploitation at the network and runtime layer — O3 flags the exploit behaviour from runtime telemetry and egress traffic even before a vulnerable build is confirmed.
Fix
Apply the linux linux kernel security patch or hotfix for CVE-2026-46259 on the affected version, following the vendor advisory for your exact build.
Workarounds
Cut exposure now: restrict the management/admin interface to trusted networks, segment the device, and apply the vendor's recommended configuration mitigations and any WAF/IPS signature. O3's runtime protection blocks the exploit chain at execution, holding the line on unpatched or end-of-life systems until you can patch.
How O3 protects you
O3 detects and blocks CVE-2026-46259 exploitation at runtime: eBPF exploit-chain detection, plus L7 egress monitoring that catches the post-exploitation callback and severs the attacker's outbound channel.

Tailored to CVE-2026-46259. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

In the Linux kernel, the following vulnerability has been resolved: procfs: fix missing RCU protection when reading real_parent in do_task_stat() When reading /proc/[pid]/stat, do_task_stat() accesses task->real_parent without proper RCU protection, which leads to: cpu 0 cpu 1 ----- ----- do_task_stat var = task->real_parent release_task call_rcu(delayed_put_task_struct) task_tgid_nr_ns(var) rcu_read_lock <--- Too late to protect tas

O3 Security · Runtime Protection

Is CVE-2026-46259 being exploited in your environment?

O3's eBPF runtime sensors and L7 egress monitoring detect and block the CVE-2026-46259 exploit chain at execution — protecting unpatched and end-of-life systems until the vendor patch is applied.

Protect my workloads How runtime protection works