CVE-2026-55833
Netty SPDY zlib header block continues decoded expansion after maxHeaderSize truncation
- Published
- Updated
- Reserved
- Assigned by
- GitHub_M
Description
Netty is a network application framework for development of protocol servers and clients. Prior to 4.1.136.Final and 4.2.16.Final, Netty SPDY header decoding continues inflating zlib-compressed header blocks after the raw header parser has exceeded `maxHeaderSize` and marked the frame truncated in `SpdyFrameCodec`, allowing a remote peer to send a small compressed `HEADERS` block that expands into much larger raw header data and causes compression-amplified CPU and allocation churn. This issue is fixed in versions 4.1.136.Final and 4.2.16.Final.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| GitHub_MCNA (assigner) | 3.1 | High7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
| NVDNVD · Analyzed | 3.1 | High7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
- EPSS (exploitation in 30 days)
- 0.66% · top 48% of all CVEs (6 Nov 2026)
- CISA SSVC
- Exploitation: none · Automatable: yes · Technical impact: partial
The list uses the assigner's score when there is one, then CISA's, then NVD's: High 7.5.
Weakness
Affected products
Affected packages
From reviewed advisories of the GitHub Advisory Database.
- Mavenio.netty:netty-codec-httpGHSA-mvh2-crg5-v77c (opens in a new tab)
References (5)
- https://github.com/netty/netty/security/advisories/GHSA-mvh2-crg5-v77c (opens in a new tab)x_refsource_CONFIRM
- https://github.com/netty/netty/commit/5b68c61f37aa4a3045cba624cbea239655c9003b (opens in a new tab)x_refsource_MISC
- https://github.com/netty/netty/commit/bb2ff68a1fb71cb4b0eb9a9e17b66c52aff680c6 (opens in a new tab)x_refsource_MISC
- https://github.com/netty/netty/releases/tag/netty-4.1.136.Final (opens in a new tab)x_refsource_MISC
- https://github.com/netty/netty/releases/tag/netty-4.2.16.Final (opens in a new tab)x_refsource_MISC
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisory GHSA-mvh2-crg5-v77c (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://trackcve.app/cve/CVE-2026-55833)Record last updated .