Is CVE-2026-100657 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-100657 being exploited in the wild.

How severe is CVE-2026-100657?

High severity, with a CVSS score of 7.5, published 26 September 2026.

Which products and versions are affected?

Netty-Codec-Stomp up to 4.1.137.Final; 4.2.0.Final through 4.2.17.Final.

Is there a fix for CVE-2026-100657?

A patch was published on 2026-09-26: Fixed in 4.1.138.Final and 4.2.18.Final Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

How is CVE-2026-100657 attacked?

It is attacked over the network, in a software library.

Am I affected by CVE-2026-100657?

Check whether you run Netty-Codec-Stomp at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-100657: Netty STOMP codec ByteBuf leak in StompSubframeDecoder

CVE-2026-100657 · Severity: high · CVSS 7.5 · Published 2026-09-26

Netty's STOMP codec is a network protocol handler used in messaging applications. A memory leak allows a remote attacker to exhaust server memory by sending incomplete frame messages, one buffer per connection, causing the application to eventually run out of memory and crash. No authentication is required since the attack begins immediately upon connection.

Vendors: Netty.

Quick answers

Is CVE-2026-100657 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-100657 being exploited in the wild.
How severe is CVE-2026-100657?: High severity, with a CVSS score of 7.5, published 26 September 2026.
Which products and versions are affected?: Netty-Codec-Stomp up to 4.1.137.Final; 4.2.0.Final through 4.2.17.Final.
Is there a fix for CVE-2026-100657?: A patch was published on 2026-09-26: Fixed in 4.1.138.Final and 4.2.18.Final Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-100657 attacked?: It is attacked over the network, in a software library.
Am I affected by CVE-2026-100657?: Check whether you run Netty-Codec-Stomp at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

Technical details

The StompSubframeDecoder allocates a ByteBuf and stores it in an instance field while waiting for a terminating NUL byte after the frame body is received. If the byte never arrives, the buffer is never released because: (1) the replay Signal thrown extends Error not Exception, bypassing the catch(Exception) release path; (2) the decoder does not override handlerRemoved0 or channelInactive to clean up. A remote peer can leak one buffer per connection by sending a complete frame body without the terminating byte, causing monotonic memory exhaustion with the default PooledByteBufAllocator.

Affected products

Netty netty-codec-stomp up to 4.1.137.Final; 4.2.0.Final through 4.2.17.Final

Timeline

2026-09-26: disclosed
2026-09-26: patched: Fixed in 4.1.138.Final and 4.2.18.Final

References

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