Use-after-free in Linux kernel eventpoll epoll refcount handling
CVE-2025-38349 is a use-after-free vulnerability in the Linux kernel eventpoll (epoll) subsystem. The flaw arises because the code decremented the ep object reference count before releasing ep->mtx via mutex_unlock(&ep->mtx). In the non-final-reference case, another thread could acquire the mutex after it was internally released, drop its own reference, and free the ep object while the original thread was still completing mutex_unlock() and therefore still accessing the mutex structure embedded in the freed object. The issue is rooted in incorrect lifetime management of the ep object and misunderstanding of mutex semantics: mutex mutual exclusion does not guarantee object ownership during unlock. The fix moves the ep refcount decrement to after the mutex unlock, relying on the atomic refcount for lifetime management.
Are you exposed to this one?
Mallory correlates every CVE against your assets, your vendors, and active adversary campaigns. Know which vulnerabilities matter for you, not just which ones are loud.
Impact, mitigation & remediation
What it means. What to do now. Patch path, mitigations, and the assume-compromise checklist.
Impact
What an attacker gets, and what they’ve been doing with it.
Mitigation
If you can’t patch tonight, do this now.
Remediation
Patch, then assume compromise.
Exploits
No public exploits tracked yet. Mallory keeps watching.
No public exploit code observed for this vulnerability.
Affected products & vendors
Products and vendors Mallory has correlated with this vulnerability. Open in Mallory to drill down to specific CPE configurations and version ranges.
Vendor-confirmed product mapping. Mallory continuously reconciles this list against your asset inventory.
Recent activity
9 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.
High-severity kernel elevation-of-privilege issue in Net/EPoll subsystems referenced as part of the December 2025 Android bulletin’s kernel bug set.
High-severity Android kernel vulnerability referenced in the December 2025 bulletin as expanding the local kernel privilege-escalation attack surface.
A high-severity use-after-free vulnerability with an attack surface on the epoll system call interface, potentially enabling local privilege escalation or kernel-level memory corruption depending on the affected component.
The version that knows your environment.
Query your assets running an affected version, and investigate the blast radius.
Every observed campaign linking this CVE to a named adversary.
Malware families riding this exploit, with evidence and IOCs.
YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.
Cross-references every affected SKU, including bundled OEM variants.
Community discussion across Reddit, Mastodon, and other social sources.