Denial of Service attack on windows app using Netty

Description

Summary

An unsafe reading of environment file could potentially cause a denial of service in Netty.
When loaded on an Windows application, Netty attemps to load a file that does not exist. If an attacker creates such a large file, the Netty application crash.

Details

A similar issue was previously reported in https://github.com/netty/netty/security/advisories/GHSA-xq3w-v528-46rv
This issue was fixed, but the fix was incomplete in that null-bytes were not counted against the input limit.

PoC

The PoC is the same as for https://github.com/netty/netty/security/advisories/GHSA-xq3w-v528-46rv with the detail that the file should only contain null-bytes; 0x00.
When the null-bytes are encountered by the InputStreamReader, it will issue replacement characters in its charset decoding, which will fill up the line-buffer in the BufferedReader.readLine(), because the replacement character is not a line-break character.

Impact

Impact is the same as https://github.com/netty/netty/security/advisories/GHSA-xq3w-v528-46rv

Basic information

Type
reviewed
Severity
medium
Advisory on GitHub
Open advisory ↗
Repository advisory
Open repository advisory ↗
Source code
Browse source ↗
Published (advisory)
2025-02-10 18:14:47 UTC
Updated
2025-02-21 18:32:16 UTC
GitHub reviewed
2025-02-10 18:14:47 UTC
NVD published
2025-02-10

EPSS Score

Score Percentile
0.10% 26.48%

CVSS Scores

Base score Version Severity Vector
5.5 3.1
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H Click to expand
Attack vector (AV:L)
They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.

Identifiers

CWEs

CWE id Name
CWE-400 Uncontrolled Resource Consumption

Credits

  • chrisvest (reporter)
  • navzen2000 (analyst)
  • henrikplate (analyst)
  • JensBoening1337 (analyst)
  • jfposton (analyst)

Affected packages (1)

Vulnerable version ranges and first patched releases as published by GitHub.

Ecosystem Package Vulnerable range First patched Vulnerable functions
maven io.netty:netty-common < 4.1.118.Final 4.1.118.Final

References

cvelogic Threat Intelligence