Advisory details:
gitlab / maven/io.netty/netty-handler/CVE-2026-75596
| Advisory ID | gitlab/maven/io.netty/netty-handler/CVE-2026-75596 |
| Aliases |
CVE-2026-75596
GHSA-fccg-mwvh-qqg4 |
| Summary | Netty: Fragmented ClientHello records trigger quadratic pre-handshake reassembly in default SNI parsing Netty's default SNI entrypoint reparses and recopies previously received ClientHello fragments on every additional TLS handshake record. A remote peer can send a small first record that advertises a large ClientHello length and then drip the body in many tiny records, causing **superlinear (quadratic) CPU work** before the handshake completes. With 4095 one-byte fragments, the handler recopies **8,386,560 bytes** from only **24,579 bytes** on the wire — a **341× amplification** ratio. |
| Status | Published |
| Exploitability | 0.5 |
| Weighted Severity | 0.0 |
| Risk | |
| Affected and Fixed Packages | Package Details |
| Introduced and Fixed Package Commit Patches | Package Commit Patches Details |
| System | Score | Found at |
|---|---|---|
| cvssv3.1 | https://gitlab.com/gitlab-org/advisories-community/-/blob/main/maven/io.netty/netty-handler/CVE-2026-75596.yml |
No EPSS data available for this advisory.
| Patch URL | |
|---|---|
| There are no known patches. | |
| Attack Vector (AV) | Attack Complexity (AC) | Privileges Required (PR) | User Interaction (UI) | Scope (S) | Confidentiality Impact (C) | Integrity Impact (I) | Availability Impact (A) |
|---|---|---|---|---|---|---|---|
network adjacent_network local physical |
low high |
none low high |
none required |
unchanged changed |
high low none |
high low none |
high low none |
There are no SSVC decisions available.