Home/CVE/ImpactWhen an application passes user-controlled input to the upgrade option of client.request(), an attacker can inj
CVE

CVE-2026-1527

ImpactWhen an application passes user-controlled input to the upgrade option of client.request(), an attacker can inj

ImpactWhen an application passes user-controlled input to the upgrade option of client.request(), an attacker can inject CRLF sequences (\r\n) to: Inject arbitrary HTTP headers Terminate the HTTP request prematurely and smuggle raw data to non-HTTP services (Redis, Memcached, Elasticsearch) The vulnerability exists because undici writes the upgrade value directly to the socket without validating for invalid header characters: // lib/dispatcher/client-h1.js:1121 if (upgrade) { header += connection: upgrade\r\nupgrade: ${upgrade}\r\n }.

MEDIUM · CVSS 4.6 EPSS 0.00012
Monitor
  • No active-exploitation, high-EPSS, or public-exploit signals - routine patching cadence
Sigma rules0 YARA rules0
⬡

Weakness Classification

CWE-93Improper Neutralization of CRLF Sequences ('CRLF Injection')
▤

Affected Products & Versions

2
nodejs undici< 6.24.0
nodejs undici>= 7.0.0 and < 7.24.0
▤

Affected Packages

1
Language-ecosystem packages (from OSV) tied to this CVE, with the version that fixes it - the dependency-level detail NVD doesn’t carry.
npm undici MODERATE fixed in 6.24.0
▣

Scoring & Timeline

4.6
MEDIUM · CVSS v3.1 · ce714d77-add3-4f53-aff5-83d477b104bb
View on NVD
Attack Vector
Network Adjacent Local Physical
Attack Complexity
Low High
Privileges Required
None Low High
User Interaction
None Required
Scope
Unchanged Changed
Confidentiality
None Low High
Integrity
None Low High
Availability
None Low High
Published to NVD12 Mar 2026 · 09:16 PM
CVSS VectorCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:L/A:N
SSVC triage · cisa-vulnrichment
Exploitation
none
Automatable
no
Technical impact
partial
SSVC asks the questions that actually drive patch urgency: is it being exploited, can attacks be automated, and how total is the impact.
⚑

Vendor Advisories

3
rhsaRHSA-2026:7350Important
rhsaRHSA-2026:7670Important
rhsaRHSA-2026:7675Important
🔗

References & Sources

3
Source URLs (vendor pages, mailing lists, write-ups). Exploit/PoC links are in their own section above to avoid duplication.
https://cna.openjsf.org/security-advisories.htmlVendor Advisory
https://github.com/nodejs/undici/security/advisories/GHSA-4992-7rv2-5pvqMitigationPatchVendor Advisory
https://hackerone.com/reports/3487198Permissions Required
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