Medium

Netty vulnerable to HTTP Response splitting from assigning header value iterator

  • Disclosed: 12.12.2022
  • Updated: 11.10.2026 12:22

Impact

When calling DefaultHttpHeaders.set with an iterator of values (as opposed to a single given value), header value validation was not performed, allowing malicious header values in the iterator to perform HTTP Response Splitting.

Patches

The necessary validation was added in Netty 4.1.86.Final.

Workarounds

Integrators can work around the issue by changing the DefaultHttpHeaders.set(CharSequence, Iterator<?>) call, into a remove() call, and call add() in a loop over the iterator of values.

References

HTTP Response Splitting CWE-113: Improper Neutralization of CRLF Sequences in HTTP Headers

For more information

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Affected software

Click a technology to see all vulnerabilities affecting it.

PlatformPackageVulnerable versionsFixed in
Java / Kotlin (Maven) io.netty:netty-codec-http >= 4.1.83.Final, < 4.1.86.Final 4.1.86.Final

References

CVSS score 6.5/10
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
Weakness (CWE)
CWE-113, CWE-436
Platform
Java / Kotlin (Maven)
Package
io.netty:netty-codec-http
Disclosed
12.12.2022
Updated
11.10.2026 12:22

Sources and licenses

OSV / GitHub Advisory Database - GHSA-hh82-3pmq-7frp - CC BY 4.0

Vulnerability history: io.netty:netty-codec-http

All published vulnerabilities of this package (Java / Kotlin (Maven)), newest first. Shows whether this is a one-off slip or a package that needs watching.

All (24) in the archive
Total entries
24
First → latest
02.2020 08.2026
Without a fix
0
Exploited in attacks
0

Severity breakdown

  • Critical 1
  • High 6
  • Medium 16
  • Low 1

Disclosures per year

  1. 2020: 1
  2. 2021: 2
  3. 2022: 2
  4. 2023: 0
  5. 2024: 1
  6. 2025: 2
  7. 2026: 16
Severity:
  1. High CVE-2026-56745 >= 4.2.0.Final, < 4.2.16.Final, >= 4.1.0.Final, < 4.1.136.Final 4.2.16.Final, 4.1.136.Final
  2. High · 7.5 CVE-2026-55833 >= 4.2.0.Final, < 4.2.16.Final, >= 4.1.0.Final, < 4.1.136.Final 4.2.16.Final, 4.1.136.Final
  3. High · 7.5 CVE-2026-55831 >= 4.2.0.Final, < 4.2.16.Final, >= 4.1.0.Final, < 4.1.136.Final 4.2.16.Final, 4.1.136.Final
  4. High · 7.5 CVE-2026-42587 >= 4.2.0.Alpha1, < 4.2.13.Final, < 4.1.133.Final 4.2.13.Final, 4.1.133.Final
  5. High · 7.3 CVE-2026-42584 >= 4.2.0.Alpha1, < 4.2.13.Final, < 4.1.133.Final 4.2.13.Final, 4.1.133.Final
  6. High · 7.5 CVE-2026-33870 < 4.1.132.Final, >= 4.2.0.Alpha1, < 4.2.10.Final 4.1.132.Final, 4.2.10.Final
  7. Netty vulnerable to HTTP Response splitting from assigning header value iterator this entry
    Medium · 6.5 CVE-2022-41915 >= 4.1.83.Final, < 4.1.86.Final 4.1.86.Final
  8. Critical · 9.1 CVE-2019-20444 < 4.1.44 4.1.44

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