CVE-2022-35256: The llhttp parser in the http module in Node v18.7.0 does not correctly handle header fields that are not term

Q: How do I fix CVE-2022-35256?

node.js: upgrade to 14.20.1, 16.17.1, 18.9.1; llhttp: upgrade to 6.0.10; sinec ins: upgrade to 1.0. Exact commands for each OS are on this page.

Q: Is CVE-2022-35256 being exploited?

CVE-2022-35256 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2022-35256 affect?

CVE-2022-35256 affects node.js, llhttp, sinec ins. Severity is medium (CVSS 6.5). The llhttp parser in the http module in Node v18.7.0 does not correctly handle header fields that are not terminated with CLRF. This may result in HTTP Request Smuggling.

Q: How urgent is CVE-2022-35256?

Priority 59/100. Public exploit reference; Remotely exploitable, no login, no user action; On your watchlist

This week

MEDIUM 6.5REMOTEWATCHLISTUPGRADEUPGRADEUPGRADE

CVE-2022-35256 is a medium-severity flaw (CVSS 6.5) affecting node.js, llhttp, sinec ins. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

The llhttp parser in the http module in Node v18.7.0 does not correctly handle header fields that are not terminated with CLRF. This may result in HTTP Request Smuggling.

Why this priority

Public exploit reference
Remotely exploitable, no login, no user action
On your watchlist

A fixed release or distro patch exists.

Risk facts

CVSS score	6.5 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	2.8% (top 14%)
CISA exploited list	No
Weakness	CWE-444
Published	2022-12-05
Last modified	2026-06-17

Publisher (CNA): HackerOne · Vendor: debian · llhttp · nodejs · siemens

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2022-12-05 22:15 UTCPublished CVE record published
2026-06-17 04:51 UTCUpdated Record last modified

nodejs node.js UPGRADE

Affected: >= 14.0.0 and <= 14.14.0 · >= 14.15.0 and < 14.20.1 · >= 16.0.0 and <= 16.12.0 · >= 16.13.0 and < 16.17.1 · >= 18.0.0 and < 18.9.1

Fixed in: 14.20.1, 16.17.1, 18.9.1

Safe to downgrade to: a release before 14.0.0

1. Check installed version

apt-cache policy node.js || rpm -q node.js || node.js --version

2. UPGRADE to 14.20.1 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade node.js

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade node.js

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

3. If no update is available yet, DOWNGRADE to a release before 14.0.0 (Debian / Ubuntu)

apt-cache madison node.js sudo apt install node.js=<VERSION_BEFORE_14.0.0> sudo apt-mark hold node.js

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list node.js sudo dnf downgrade node.js-<VERSION_BEFORE_14.0.0> sudo dnf versionlock add node.js

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

llhttp llhttp UPGRADE

Affected: < 6.0.10

Fixed in: 6.0.10

Safe to downgrade to: no unaffected older release

1. Check installed version

npm ls llhttp

2. UPGRADE to 6.0.10

npm install llhttp@">=6.0.10"

siemens sinec ins UPGRADE

Affected: < 1.0 · 1.0 · 1.0 sp1 · 1.0 sp2

Fixed in: 1.0

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy sinec-ins || rpm -q sinec-ins || sinec-ins --version

2. UPGRADE to 1.0 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade sinec-ins

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade sinec-ins

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

debian debian linux MITIGATE

Affected: 11.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 11.0

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2022-35256?

node.js: upgrade to 14.20.1, 16.17.1, 18.9.1; llhttp: upgrade to 6.0.10; sinec ins: upgrade to 1.0. Exact commands for each OS are on this page.

Is CVE-2022-35256 being exploited?

CVE-2022-35256 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2022-35256 affect?

CVE-2022-35256 affects node.js, llhttp, sinec ins. Severity is medium (CVSS 6.5). The llhttp parser in the http module in Node v18.7.0 does not correctly handle header fields that are not terminated with CLRF. This may result in HTTP Request Smuggling.

How urgent is CVE-2022-35256?

Priority 59/100. Public exploit reference; Remotely exploitable, no login, no user action; On your watchlist

Software pages

Node.js vulnerabilities · Debian vulnerabilities · Siemens vulnerabilities

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References

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