Staging Environment: Content and features may be unstable or change without notice.
Advisory details: vulnrichment / CVE-2026-42587
Advisory ID vulnrichment/CVE-2026-42587
Aliases
Summary Netty is an asynchronous, event-driven network application framework. Prior to 4.2.13.Final and 4.1.133.Final, HttpContentDecompressor accepts a maxAllocation parameter to limit decompression buffer size and prevent decompression bomb attacks. This limit is correctly enforced for gzip and deflate encodings via ZlibDecoder, but is silently ignored when the content encoding is br (Brotli), zstd, or snappy. An attacker can bypass the configured decompression limit by sending a compressed payload with Content-Encoding: br instead of Content-Encoding: gzip, causing unbounded memory allocation and out-of-memory denial of service. The same vulnerability exists in DelegatingDecompressorFrameListener for HTTP/2 connections. This vulnerability is fixed in 4.2.13.Final and 4.1.133.Final.
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
Weaknesses (1)
CWE-400 Uncontrolled Resource Consumption
System Score Found at
cvssv3.1 7.5
ssvc Track
Reference id Reference type URL
https://github.com/netty/netty/security/advisories/GHSA-f6hv-jmp6-3vwv
No exploits are available.

No EPSS data available for this advisory.

Patch URL
There are no known patches.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Found at None
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
Vector: SSVCv2/E:P/A:Y/T:P/P:M/B:A/M:M/D:T/2026-05-13T18:43:31Z/ Found at None

Vector: SSVCv2/E:P/A:Y/T:P/P:M/B:A/M:M/D:T/2026-05-13T18:43:31Z/

Decision: Track

Source URL: https://github.com/cisagov/vulnrichment/blob/develop/2026/42xxx/CVE-2026-42587.json

Source Advisory: vulnrichment/CVE-2026-42587

View SSVC decision tree 
[{'Exploitation': 'poc'},
 {'Automatable': 'yes'},
 {'Technical Impact': 'partial'},
 {'Mission Prevalence': 'minimal'},
 {'Public Well-being Impact': 'material'},
 {'Mission & Well-being': 'medium'}]