CVE-2025-25193 Denial of Service attack on windows app using Netty
An attacker can cause a denial of service in Windows applications using Netty by creating a large file that triggers an unsafe read during environment file loading.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2025-25193?
CVE-2025-25193 is a medium-severity denial of service vulnerability in Netty Netty, published on 10 Feb 2025. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
Netty, an asynchronous, event-driven network application framework, has a vulnerability in versions up to and including 4.1.118.Final. An unsafe reading of environment file could potentially cause a denial of service in Netty. When loaded on an Windows application, Netty attempts to load a file that does not exist. If an attacker creates such a large file, the Netty application crash. A similar issue was previously reported as CVE-2024-47535. This issue was fixed, but the fix was incomplete in that null-bytes were not counted against the input limit. Commit d1fbda62d3a47835d3fb35db8bd42ecc205a5386 contains an updated fix.
Weakness: CWE-400
Which versions are affected by CVE-2025-25193?
2 open source packages ship an affected version, including io.netty:netty-common. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
io.netty:netty-common Maven | All versions | 4.1.118.Final |
io.netty:netty-common Maven | All versions | 4.1.118.Final |
Products include Netty Netty.
How do I fix CVE-2025-25193?
Upgrade io.netty:netty-common to 4.1.118.Final or later.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2025-25193 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2025-25193 exists.
Other vulnerabilities in Netty Netty
- CVE-2026-75595 Netty: SNI Routing Bypass via Fragmented TLS ClientHello Causing Fallback to Default SslContext
- CVE-2026-75596 Netty: Fragmented ClientHello records trigger quadratic pre-handshake reassembly in default SNI parsing
- CVE-2026-59901 Netty Bzip2Decoder: Infinite Loop in RLE State Machine Leads to Event-Loop Thread Hang
- CVE-2026-55851 Netty codec-haproxy: Signed-Byte Sentinel Collision in HAProxyMessageDecoder Leads to Unbounded Memory Exhaustion
- CVE-2026-56745 Netty SpdyHttpDecoder: ByteBuf Reference Leak on RST_STREAM Leads to Native Memory Exhaustion
Sources
Also known as CLEANSTART-2026-BA63285, CLEANSTART-2026-BB34583, CLEANSTART-2026-HP63301, CLEANSTART-2026-JO61169, CLEANSTART-2026-SY79520, CLSA-2025-1760313985 and 21 more.