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© 2026 FAUCET Technologies LLC. All rights reserved.

CVE-2026-42587

35
FAUCET Score

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.

First published: May 13, 2026Last modified: May 13, 2026

Impacted Technologies

VendorProductVersion(s)CPE
< 4.1.133CPE matchmatch criteria
cpe:2.3:a:netty:netty:*:*:*:*:*:*:*:*
>= 4.2.0, < 4.2.13CPE matchmatch criteria
cpe:2.3:a:netty:netty:*:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

7.5HIGH

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
HIGH
Exploitability Score
3.9
Impact Score
3.6
CvssVersion
3.1

Exploit Intelligence

EPSS Score
0.99%
Probability of exploitation in next 30 days
EPSS Percentile
58.9%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.0099 is in the 34th percentile among its peer group of 51,506 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.1 Bluesky, 0.1 Mastodon, and 0.4 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.1 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (5)

mavenpatch availablevia ghsa
Product: io.netty:netty-codec-httpFixed in: 4.2.13.Final
mavenpatch availablevia ghsa
Product: io.netty:netty-codec-http2Fixed in: 4.2.13.Final
mavenpatch availablevia ghsa
Product: io.netty:netty-codec-httpFixed in: 4.1.133.Final
mavenpatch availablevia ghsa
Product: io.netty:netty-codec-http2Fixed in: 4.1.133.Final
github_advisoryworkaround availablevia nvd_reference
View patch

Vendor Advisories (1)

mavenGHSA-f6hv-jmp6-3vwvhigh

Netty: HttpContentDecompressor maxAllocation bypass when Content-Encoding set to br/zstd/snappy leads to decompression bomb DoS

May 7, 2026

References

access.redhat.com / errata/RHSA-2026:23808
access.redhat.com / errata/RHSA-2026:24502
access.redhat.com / errata/RHSA-2026:25123
access.redhat.com / errata/RHSA-2026:28010
access.redhat.com / errata/RHSA-2026:34608
access.redhat.com / errata/RHSA-2026:36820
access.redhat.com / errata/RHSA-2026:37390
access.redhat.com / errata/RHSA-2026:41951
access.redhat.com / errata/RHSA-2026:42644
access.redhat.com / security/cve/CVE-2026-42587
bugzilla.redhat.com / show_bug.cgi
security.access.redhat.com / data/csaf/v2/vex/2026/cve-2026-42587.json
github.com / netty/netty/security/advisories/GHSA-f6hv-jmp6-3vwv
ExploitMitigationVendor Advisory