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Full vulnerability report · 2023
CVE-2023-23936High confidence

CRLF Injection in Nodejs ‘undici’ via host

nodejs · undici

6.5MediumCVSS 3.1
Recommended action
Within 7 days

Medium technical severity with public exploit material referenced by a structured source; prioritise exposed affected systems while verifying vendor guidance.

Patch available
Optional official sources

National CERT insights
?CERT means Computer Emergency Response Team; CSIRT is the closely related term Computer Security Incident Response Team.

Select the national-authority views to include. The exact source language is shown on each matched advisory. Your choice is remembered on this device and encoded in the shareable URL.

Official European source

ENISA European Vulnerability Database

Official EUVD identifiers, advisory evidence and known-exploited context. Missing fields are not treated as evidence of low risk.

1 current
ENISA EUVD identifier

EUVD-2023-0633

No EUVD known-exploited evidence

ENISA has published the identifier mapping but no EUVD description has been stored yet.

EUVD state
Present in the current official mapping
Known exploitation
Not present in the current ENISA EUVD known-exploited dataset. This is not proof of no exploitation.
ENISA score
Not supplied in the stored EUVD record
Advisory evidence
No linked advisory details stored yet
Recommended actionWithin 7 days

Medium technical severity with public exploit material referenced by a structured source; prioritise exposed affected systems while verifying vendor guidance.

Patch available
01

What, why and how

Undici is an HTTP/1.1 client for Node.js. Starting with version 2.0.0 and prior to version 5.19.1, the undici library does not protect `host` HTTP header from CRLF injection vulnerabilities. This issue is patched in Undici v5.19.1. As a workaround, sanitize the `headers.host` string before passing to undici.

What

Undici is an HTTP/1.1 client for Node.js. Starting with version 2.0.0 and prior to version 5.19.1, the undici library does not protect `host` HTTP header from CRLF injection vulnerabilities. This issue is patched in Undici v5.19.1. As a workaround, sanitize the `headers.host` string before passing to undici.

Why

The product uses CRLF (carriage return line feeds) as a special element, e.g. to separate lines or records, but it does not neutralize or incorrectly neutralizes CRLF sequences from inputs.

How

An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.

What

Undici is an HTTP/1.1 client for Node.js. Starting with version 2.0.0 and prior to version 5.19.1, the undici library does not protect `host` HTTP header from CRLF injection vulnerabilities. This issue is patched in Undici v5.19.1. As a workaround, sanitize the `headers.host` string before passing to undici.

Why

The product uses CRLF (carriage return line feeds) as a special element, e.g. to separate lines or records, but it does not neutralize or incorrectly neutralizes CRLF sequences from inputs.

How

An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.

02

Exploit reality and attack path

CVSS severity, EPSS forecast probability, public exploit material and CISA-confirmed exploitation are separate signals.

Observed exploitation
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
No confirmed evidence

No CISA KEV match was present at the last successful refresh. This means no confirmation from that source, not proof of no exploitation.

Public PoC / exploit material
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
Reference recorded

A structured CVE source labels at least one public reference as exploit material. BlackTree has not independently validated that it is safe, reliable or weaponised.

Likely attack path
a network path → Improper Neutralization of CRLF Sequences ('CRLF Injection') → cause the confidentiality, integrity or availability impact described by the vendor
Attack surface
Network
Privileges required
None: unauthenticated exploitation is possible
User interaction
None
Attack complexity
Low: no specialised conditions are recorded
Security boundary
Unchanged: impact remains within the vulnerable component's security authority
Weakness
?CWE means Common Weakness Enumeration: a standard category for the underlying weakness.
CWE-93

CWE-93: Improper Neutralization of CRLF Sequences ('CRLF Injection'). The product uses CRLF (carriage return line feeds) as a special element, e.g. to separate lines or records, but it does not neutralize or incorrectly neutralizes CRLF sequences from inputs.

CVSS vector
?CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N

Common Vulnerability Scoring System 3.1: the compact vector below is decoded into plain language.

AVNetworkAttack vector: The vulnerable component can be reached over a network.ACLowAttack complexity: No specialised conditions are required beyond attacker-controlled input.PRNonePrivileges required: The attacker does not need an account or existing privileges.UINoneUser interaction: No action by another user is required.SUnchangedScope: The security impact remains within the vulnerable component's authority.CLowConfidentiality impact: A successful attack can cause a limited loss.ILowIntegrity impact: A successful attack can cause a limited loss.ANoneAvailability impact: No direct loss is represented by this metric.
Post-exploitation / living off the land
No specific living-off-the-land technique is confirmed in the structured sources. Monitor normal administration tools for activity inconsistent with the affected service's baseline.
NetworkUnauthenticatedCWE-93Public exploit reference
A

Official authority intelligence

Only matched European and national findings are included. Language selectors and unavailable sources are omitted.

BSI · German · WID-SEC-W-2023-1424Xerox FreeFlow Print Server für Solaris: Mehrere Schwachstellen

Ein Angreifer kann mehrere Schwachstellen in Xerox FreeFlow Print Server ausnutzen, um die Vertraulichkeit, Verfügbarkeit und Integrität des Systems zu gefährden.

Official advisory
BSI · German · WID-SEC-W-2023-0414Node.js: Mehrere Schwachstellen

Ein entfernter, anonymer oder authentisierter Angreifer kann mehrere Schwachstellen in Node.js ausnutzen, um Sicherheitsmaßnahmen zu umgehen, vertrauliche Informationen offenzulegen und einen Denial-of-Service-Zustand zu verursachen.

Official advisory
CERT-FR · French · CERTFR-2025-AVI-0170Multiples vulnérabilités dans les produits IBM

ord?id=CVE-2021-44906 Référence CVE CVE-2022-24999 https://www.cve.org/CVERecord?id=CVE-2022-24999 Référence CVE CVE-2022-25881 https://www.cve.org/CVERecord?id=CVE-2022-25881 Référence CVE CVE-2022-37434 https://www.cve.org/CVERecord?id=CVE-2022-37434 Référence CVE CVE-2022-48554 https://www.cve.org/CVERecord?id=CVE-2022-48554 Référence CVE CVE-2022-4904 https://www.cve.org/CVERecord?id=CVE-2022-4904 Référence CVE CVE-2023-23918 https://www.cve.org/CVERecord?id=CVE-2023-23918 Référence CVE CVE-2023-23919 https://www.cve.org/CVERecord?id=CVE-2023-23919 Référence CVE CVE-2023-23920 https://www.cve.org/CVERecord?id=CVE-2023-23920 Référence CVE CVE-2023-23936 https://www.cve.org/CVERecord?id=CVE-2023-23936 Référence CVE CVE-2023-24807 https://www.cve.org/CVERecord?id=CVE-2023-24807 Référence CVE CVE-2023-26136 https://www.cve.org/CVERecord?id=CVE-2023-26136 Référence CVE CVE-2023-28155 https://www.cve.org/CVERecord?id=CVE-2023-28155 Référence CVE CVE-2023-28523 https://www.cve.org/CVERecord?id=CVE-2023-28523 Référence CVE CVE-2023-28526 https://www.cve.org/CVERecord?id=CVE-2023-28526 Référence CVE CVE-2023-28527 https://www.cve.org/CVERecord?id=CVE-2023-28527 Référence CVE CVE-2023-31124 https://www.cve.org/CVERecord?id=CVE-2023-31124 Référence CVE CVE-2023-31130 https://www.cve.org/CVERecord?id=

Official advisory
CERT-FR · French · CERTFR-2024-AVI-1051Multiples vulnérabilités dans les produits IBM

d?id=CVE-2023-21967 Référence CVE CVE-2023-21968 https://www.cve.org/CVERecord?id=CVE-2023-21968 Référence CVE CVE-2023-22045 https://www.cve.org/CVERecord?id=CVE-2023-22045 Référence CVE CVE-2023-22049 https://www.cve.org/CVERecord?id=CVE-2023-22049 Référence CVE CVE-2023-22067 https://www.cve.org/CVERecord?id=CVE-2023-22067 Référence CVE CVE-2023-22081 https://www.cve.org/CVERecord?id=CVE-2023-22081 Référence CVE CVE-2023-23918 https://www.cve.org/CVERecord?id=CVE-2023-23918 Référence CVE CVE-2023-23919 https://www.cve.org/CVERecord?id=CVE-2023-23919 Référence CVE CVE-2023-23920 https://www.cve.org/CVERecord?id=CVE-2023-23920 Référence CVE CVE-2023-23936 https://www.cve.org/CVERecord?id=CVE-2023-23936 Référence CVE CVE-2023-24807 https://www.cve.org/CVERecord?id=CVE-2023-24807 Référence CVE CVE-2023-24998 https://www.cve.org/CVERecord?id=CVE-2023-24998 Référence CVE CVE-2023-2597 https://www.cve.org/CVERecord?id=CVE-2023-2597 Référence CVE CVE-2023-26159 https://www.cve.org/CVERecord?id=CVE-2023-26159 Référence CVE CVE-2023-33850 https://www.cve.org/CVERecord?id=CVE-2023-33850 Référence CVE CVE-2023-38264 https://www.cve.org/CVERecord?id=CVE-2023-38264 Référence CVE CVE-2023-38737 https://www.cve.org/CVERecord?id=CVE-2023-38737 Référence CVE CVE-2023-39332 https://www.cve.org/CVERecord?id=CV

Official advisory
CERT-FR · French · CERTFR-2024-AVI-0145Multiples vulnérabilités dans les produits IBM

d?id=CVE-2023-21939 Référence CVE CVE-2023-21954 https://www.cve.org/CVERecord?id=CVE-2023-21954 Référence CVE CVE-2023-21967 https://www.cve.org/CVERecord?id=CVE-2023-21967 Référence CVE CVE-2023-21968 https://www.cve.org/CVERecord?id=CVE-2023-21968 Référence CVE CVE-2023-22081 https://www.cve.org/CVERecord?id=CVE-2023-22081 Référence CVE CVE-2023-23916 https://www.cve.org/CVERecord?id=CVE-2023-23916 Référence CVE CVE-2023-23918 https://www.cve.org/CVERecord?id=CVE-2023-23918 Référence CVE CVE-2023-23919 https://www.cve.org/CVERecord?id=CVE-2023-23919 Référence CVE CVE-2023-23920 https://www.cve.org/CVERecord?id=CVE-2023-23920 Référence CVE CVE-2023-23936 https://www.cve.org/CVERecord?id=CVE-2023-23936 Référence CVE CVE-2023-24532 https://www.cve.org/CVERecord?id=CVE-2023-24532 Référence CVE CVE-2023-24534 https://www.cve.org/CVERecord?id=CVE-2023-24534 Référence CVE CVE-2023-24536 https://www.cve.org/CVERecord?id=CVE-2023-24536 Référence CVE CVE-2023-24537 https://www.cve.org/CVERecord?id=CVE-2023-24537 Référence CVE CVE-2023-24538 https://www.cve.org/CVERecord?id=CVE-2023-24538 Référence CVE CVE-2023-24539 https://www.cve.org/CVERecord?id=CVE-2023-24539 Référence CVE CVE-2023-24540 https://www.cve.org/CVERecord?id=CVE-2023-24540 Référence CVE CVE-2023-2597 https://www.cve.org/CVERecord?id=C

Official advisory
CERT-FR · French · CERTFR-2023-AVI-0886Multiples vulnérabilités dans Tenable Identity Exposure

De multiples vulnérabilités ont été découvertes dans Tenable Identity Exposure. Certaines d'entre elles permettent à un attaquant de provoquer un problème de sécurité non spécifié par l'éditeur, une exécution de code arbitraire à distance et un déni de service à distance.

Official advisory
CERT-FR · French · CERTFR-2023-AVI-0504Multiples vulnérabilités dans les produits IBM

d?id=CVE-2022-42889 Référence CVE CVE-2022-43548 https://www.cve.org/CVERecord?id=CVE-2022-43548 Référence CVE CVE-2022-43927 https://www.cve.org/CVERecord?id=CVE-2022-43927 Référence CVE CVE-2022-43929 https://www.cve.org/CVERecord?id=CVE-2022-43929 Référence CVE CVE-2022-43930 https://www.cve.org/CVERecord?id=CVE-2022-43930 Référence CVE CVE-2022-46175 https://www.cve.org/CVERecord?id=CVE-2022-46175 Référence CVE CVE-2023-23918 https://www.cve.org/CVERecord?id=CVE-2023-23918 Référence CVE CVE-2023-23919 https://www.cve.org/CVERecord?id=CVE-2023-23919 Référence CVE CVE-2023-23920 https://www.cve.org/CVERecord?id=CVE-2023-23920 Référence CVE CVE-2023-23936 https://www.cve.org/CVERecord?id=CVE-2023-23936 Référence CVE CVE-2023-24532 https://www.cve.org/CVERecord?id=CVE-2023-24532 Référence CVE CVE-2023-24537 https://www.cve.org/CVERecord?id=CVE-2023-24537 Référence CVE CVE-2023-24539 https://www.cve.org/CVERecord?id=CVE-2023-24539 Référence CVE CVE-2023-24540 https://www.cve.org/CVERecord?id=CVE-2023-24540 Référence CVE CVE-2023-24807 https://www.cve.org/CVERecord?id=CVE-2023-24807 Référence CVE CVE-2023-25165 https://www.cve.org/CVERecord?id=CVE-2023-25165 Référence CVE CVE-2023-25930 https://www.cve.org/CVERecord?id=CVE-2023-25930 Référence CVE CVE-2023-26021 https://www.cve.org/CVERecord?id=

Official advisory
CERT-FR · French · CERTFR-2023-AVI-0337Multiples vulnérabilités dans les produits IBM

d?id=CVE-2022-41854 Référence CVE CVE-2022-41881 https://www.cve.org/CVERecord?id=CVE-2022-41881 Référence CVE CVE-2022-41915 https://www.cve.org/CVERecord?id=CVE-2022-41915 Référence CVE CVE-2022-42003 https://www.cve.org/CVERecord?id=CVE-2022-42003 Référence CVE CVE-2022-42004 https://www.cve.org/CVERecord?id=CVE-2022-42004 Référence CVE CVE-2022-42889 https://www.cve.org/CVERecord?id=CVE-2022-42889 Référence CVE CVE-2023-23918 https://www.cve.org/CVERecord?id=CVE-2023-23918 Référence CVE CVE-2023-23919 https://www.cve.org/CVERecord?id=CVE-2023-23919 Référence CVE CVE-2023-23920 https://www.cve.org/CVERecord?id=CVE-2023-23920 Référence CVE CVE-2023-23936 https://www.cve.org/CVERecord?id=CVE-2023-23936 Référence CVE CVE-2023-24807 https://www.cve.org/CVERecord?id=CVE-2023-24807 Référence CVE CVE-2023-26021 https://www.cve.org/CVERecord?id=CVE-2023-26021 Référence CVE CVE-2023-29255 https://www.cve.org/CVERecord?id=CVE-2023-29255 Référence CVE CVE-2023-29257 https://www.cve.org/CVERecord?id=CVE-2023-29257 Gestion détaillée du document le 25 avril 2023 Version initiale le 25 avril 2023 Ajout de référence CVE Alertes Avis Bulletins d’actualités Mentions légales Conditions générales À propos Contact cyber.gouv.fr service-public.fr legifrance.gouv.fr info.gouv.fr france.fr info.gouv.fr/risques Pre

Official advisory
03

Patch and workaround

Operational remediation based on structured source evidence.

Status
?Patch availability is based on structured fixed-version fields and authoritative update references. If no fix is verified, check the vendor advisory before making a change.
Patch available
Affected
>=2.0.0, < 5.19.1
Fixed
An authoritative update reference is available, but the fixed version is not recorded in the structured CVE fields. Check the linked vendor advisory for the applicable release.
Action
Review the linked authoritative reference and apply the recorded fixed release appropriate to the affected product branch.
Workaround
No verified workaround is recorded. If business-safe, reduce exposure to the affected interface and allow only trusted sources until authoritative guidance is available.
04

Evidence and provenance

Published 16 Feb 2023 · Last source change 10 Mar 2025, 21:10 UTC · CWE-93 · Improper Neutralization of CRLF Sequences ('CRLF Injection')

CVE recordCVE.org · 5.1
CVSS sourceCNA
EPSS source
?The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.
FIRST · tracked since 2026-08-14
European sourceENISA EUVD · EUVD-2023-0633
Product sourceCNA
Remediation sourceCVE/CNA references
CWE sourceCNA
NVD statusNVD modified after enrichment

Core structured fields are present and their contributing authorities are shown above.

Material change intelligence

What changed after publication

View recent updates →

No material field changes have been recorded since change tracking began. Routine source refreshes and cosmetic edits are intentionally excluded.

Material fields only · duplicate refreshes suppressed · history retained for the configured operational retention period
Technical terms and abbreviations used in this report
CVE
Common Vulnerabilities and Exposures: the public identifier for one disclosed vulnerability.
CVSS
Common Vulnerability Scoring System: a technical severity framework; it is not patching priority by itself.
EPSS
Exploit Prediction Scoring System: FIRST's estimate of the probability that exploitation activity will be observed in the next 30 days; it is a forecast, not confirmation.
CWE
Common Weakness Enumeration: the standard category describing the underlying software or hardware weakness.
CNA
CVE Numbering Authority: an organisation authorised to assign and publish CVE records.
CISA ADP
Cybersecurity and Infrastructure Security Agency Authorized Data Publisher: structured enrichment added to a CVE record.
NVD
National Vulnerability Database: NIST's enrichment service for CVE records.
CERT / CSIRT
A computer security incident response team that publishes warnings or coordinates incident response.
PoC
Proof of concept: public material that demonstrates or helps reproduce exploitation.
CSAF
Common Security Advisory Framework: a machine-readable format for security advisories.
LoTL
Living off the land: abuse of legitimate tools or system functions during an attack.
Free version - for non-commercial use only.CVE-2023-23936 · cve.blacktree.nl