How severe is GHSA-fghv-69vj-qj49?

No CVSS score has been assigned to GHSA-fghv-69vj-qj49 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by GHSA-fghv-69vj-qj49?

GHSA-fghv-69vj-qj49 affects the following packages: io.netty:netty-codec-http (Maven), io.netty:netty-codec-http (Maven). Ecosystems affected: Maven.

How do I fix GHSA-fghv-69vj-qj49?

Update io.netty:netty-codec-http to 4.1.125.Final or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-fghv-69vj-qj49 is resolved across your whole dependency graph.

How do I detect GHSA-fghv-69vj-qj49 in my Maven dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for io.netty:netty-codec-http, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate GHSA-fghv-69vj-qj49 if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

How does O3 Security protect against GHSA-fghv-69vj-qj49?

O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like GHSA-fghv-69vj-qj49 can be triaged on real exposure rather than presence alone.

Is GHSA-fghv-69vj-qj49 actively exploited in the wild?

No public exploit code has been indexed for GHSA-fghv-69vj-qj49 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for GHSA-fghv-69vj-qj49?

GHSA-fghv-69vj-qj49 has an EPSS (Exploit Prediction Scoring System) score of 0.7%, placing it in the 50th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is GHSA-fghv-69vj-qj49?

GHSA-fghv-69vj-qj49 is classified as CWE-444 (CWE-444). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was GHSA-fghv-69vj-qj49 published, and has it been updated?

GHSA-fghv-69vj-qj49 was published on September 4, 2025 and was last updated on September 10, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

☕ Maven

Not in CISA KEV

GHSA-fghv-69vj-qj49 — netty-codec-http

Fix: github/advisory-database#6092

GHSA-fghv-69vj-qj49 is a CWE-444 vulnerability in io.netty:netty-codec-http. A fix is available for io.netty:netty-codec-http — see the affected versions and patch details below.

Netty vulnerable to request smuggling due to incorrect parsing of chunk extensions

Also known asCVE-2025-58056

Published

Sep 4, 2025

Updated

Sep 10, 2026

Affected

2 pkgs

Patched

2 / 2

Exploits

None indexed

Exploitation data as of Sep 25, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for GHSA-fghv-69vj-qj49.

EPSS Exploitation Probability

via FIRST.org ↗

0.7%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs50th percentile — riskier than 50% of all scored CVEsHighest risk

EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.

Real-World Exposure

2 pkgs affected

☕io.netty:netty-codec-http☕io.netty:netty-codec-http

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Maven packages — download data is not available via public APIs for these ecosystems.

Description

Summary

A flaw in netty's parsing of chunk extensions in HTTP/1.1 messages with chunked encoding can lead to request smuggling issues with some reverse proxies.

Details

When encountering a newline character (LF) while parsing a chunk extension, netty interprets the newline as the end of the chunk-size line regardless of whether a preceding carriage return (CR) was found. This is in violation of the HTTP 1.1 standard which specifies that the chunk extension is terminated by a CRLF sequence (see the RFC).

This is by itself harmless, but consider an intermediary with a similar parsing flaw: while parsing a chunk extension, the intermediary interprets an LF without a preceding CR as simply part of the chunk extension (this is also in violation of the RFC, because whitespace characters are not allowed in chunk extensions). We can use this discrepancy to construct an HTTP request that the intermediary will interpret as one request but netty will interpret as two (all lines ending with CRLF, notice the LFs in the chunk extension):

POST /one HTTP/1.1
Host: localhost:8080
Transfer-Encoding: chunked

48;\nAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA\n0

POST /two HTTP/1.1
Host: localhost:8080
Transfer-Encoding: chunked

0

The intermediary will interpret this as a single request. Once forwarded to netty, netty will interpret it as two separate requests. This is a problem, because attackers can then the intermediary, as well as perform standard request smuggling attacks against other live users (see this Portswigger article).

Impact

This is a request smuggling issue which can be exploited for bypassing front-end access control rules as well as corrupting the responses served to other live clients.

The impact is high, but it only affects setups that use a front-end which:

Interprets LF characters (without preceding CR) in chunk extensions as part of the chunk extension.
Forwards chunk extensions without normalization.

Disclosure

This vulnerability was disclosed on June 18th, 2025 here: https://w4ke.info/2025/06/18/funky-chunks.html

Discussion

Discussion for this vulnerability can be found here:

Credit

Credit to @JeppW for uncovering this vulnerability.
Credit to @JLLeitschuh at Socket for coordinating the vulnerability disclosure.

Affected Packages

2 total 2 fixed

Ecosystem	Package	Vulnerable range	Fix
☕Maven	`io.netty:netty-codec-http`	all versions	4.1.125.Final`io.netty:netty-codec-http:4.1.125.Final`
☕Maven	`io.netty:netty-codec-http`	≥ 4.2.0.Alpha1&&< 4.2.5.Final	4.2.5.Final`io.netty:netty-codec-http:4.2.5.Final`

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for io.netty:netty-codec-http, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update io.netty:netty-codec-http to 4.1.125.Final or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-fghv-69vj-qj49 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like GHSA-fghv-69vj-qj49 can be triaged on real exposure rather than presence alone.

Tailored to GHSA-fghv-69vj-qj49. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Fixing This On Your OS

If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.

Red HatModerate

This issue is considered Moderate rather than Important because successful exploitation depends on a very specific deployment condition: the presence of an intermediary reverse proxy that both mishandles lone LF characters in chunk extensions and forwards them unmodified to Netty. By itself, Netty’s parsing quirk does…

Product	Fixed in	Advisory
Cryostat 4 on RHEL 9	`cryostat/cryostat-agent-init-rhel9:0.6.0-11`	RHSA-2025:21148
Red Hat AMQ Broker 7.13.2	`netty-codec-http`	RHSA-2025:17567
Red Hat build of Apache Camel 4.10.7 for Spring Boot 3.4.10	`netty-codec-http`	RHSA-2025:18028
Red Hat Build of Apache Camel 4.10 for Quarkus 3.20	`netty-codec-http`	RHSA-2025:18076
Red Hat build of Quarkus 3.15.7	`netty-codec-http`	RHSA-2025:17187
Red Hat build of Quarkus 3.20.3	`netty-codec-http`	RHSA-2025:17563
Red Hat JBoss Enterprise Application Platform	`io.netty/netty-codec-http:4.1.127.Final-redhat-00001`	RHSA-2025:17299
Red Hat JBoss Enterprise Application Platform 8.0.9	`netty-codec-http`	RHSA-2025:17318

Frequently Asked Questions

## Summary A flaw in netty's parsing of chunk extensions in HTTP/1.1 messages with chunked encoding can lead to request smuggling issues with some reverse proxies. ## Details When encountering a newline character (LF) while parsing a chunk extension, netty interprets the newline as the end of the chunk-size line regardless of whether a preceding carriage return (CR) was found. This is in violation of the HTTP 1.1 standard which specifies that the chunk extension is terminated by a CRLF sequence (see the [RFC](https://datatracker.ietf.org/doc/html/rfc9112#name-chunked-transfer-coding)). This

O3 Security · Impact-Aware SCA

Is GHSA-fghv-69vj-qj49 in your dependencies?

O3 Security finds GHSA-fghv-69vj-qj49 across Maven dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.

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