Advisory details:
github_osv / GHSA-563q-j3cm-6jxm
| Advisory ID | github_osv/GHSA-563q-j3cm-6jxm |
| Aliases |
CVE-2026-50560
|
| Summary | Netty susceptible to HTTP/2 Reset Attack with different on-the-wire signature ### Summary Netty HTTP/2 max header size handling produces attack similar to HTTP/2 Rapid Reset. ### Details There is a setting in the http2 specification called `SETTINGS_MAX_HEADER_LIST_SIZE`. According to[ the RFC](https://www.rfc-editor.org/rfc/rfc9113.html#name-defined-settings): “This advisory setting informs a peer of the maximum field section size that the sender is prepared to accept, in units of octets.” When a client sends that setting to Netty, it appears that Netty will behave as follows: - Read the request - Proxy the request to the origin - Attempt to produce a response - Create an exception while writing the headers for the response Functionally, this should be similar to the http2 reset attack, but with a different on-the-wire signature. ## Remediation When speaking with clients, Netty should potentially treat this as “advisory” and ignore it. It would be best to ignore the SETTINGS_MAX_HEADER_LIST_SIZE setting from clients (or ignore it when sending to clients). According to the spec, a server does not need to honor this advisory setting, and it appears that other http/2 implementations ignore it when acting as a server. ### Impact This is a DDoS attack similar to the HTTP/2 Rapid Reset Attack. ## Credit Jonathan Looney (Engineering, Netflix) ## Contact Ashley Tolbert (Security, Netflix) - artolbert@netflix.com |
| Status | Published |
| Exploitability | 0.5 |
| Weighted Severity | 6.2 |
| Risk | 3.1 |
| Affected and Fixed Packages | Package Details |
| Introduced and Fixed Package Commit Patches | Package Commit Patches Details |
| System | Score | Found at |
|---|---|---|
| cvssv3.1 | 5.3 | https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/06/GHSA-563q-j3cm-6jxm/GHSA-563q-j3cm-6jxm.json |
| cvssv4 | 6.9 | https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/06/GHSA-563q-j3cm-6jxm/GHSA-563q-j3cm-6jxm.json |
| generic_textual | MODERATE |
| Reference id | Reference type | URL |
|---|---|---|
| https://github.com/netty/netty | ||
| https://github.com/netty/netty/releases/tag/netty-4.1.135.Final | ||
| https://github.com/netty/netty/releases/tag/netty-4.2.15.Final | ||
| CVE-2026-50560 | https://nvd.nist.gov/vuln/detail/CVE-2026-50560 | |
| GHSA-563q-j3cm-6jxm | Other | https://github.com/netty/netty/security/advisories/GHSA-563q-j3cm-6jxm |
| rfc9113.html#name-defined-settings | Other | https://www.rfc-editor.org/rfc/rfc9113.html#name-defined-settings |
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 |
| Attack Vector (AV) | Attack Complexity (AC) | Attack Requirements (AT) | Privileges Required (PR) | User Interaction (UI) | Vulnerable System Impact Confidentiality (VC) | Vulnerable System Impact Integrity (VI) | Vulnerable System Impact Availability (VA) | Subsequent System Impact Confidentiality (SC) | Subsequent System Impact Integrity (SI) | Subsequent System Impact Availability (SA) |
|---|---|---|---|---|---|---|---|---|---|---|
network adjacent local physical |
low high |
none present |
none low high |
none passive active |
high low none |
high low none |
high low none |
high low none |
high low none |
high low none |
There are no SSVC decisions available.