Skip to main content

CVE detail

CVE-2026-1527

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` }

CVSS 4.6 · MediumBuzz score 25.4

Buzz score

Why this CVE is surfacing

Buzz score total 25.4

This all-time snapshot uses the same composite formula as Trending across a 30-year evidence window, rather than a current rolling window.

Buzz score components · mention 13.9 · diversity 11.5 · KEV 0.0 · OTX 0.0 · PoC 0.0
Mention score
13.9
3 evidence mentions in the snapshot
Diversity score
11.5
3 sources across 2 categories
KEV score
0.0
No KEV entry observed
OTX score
0.0
0 OTX pulses
PoC score
0.0
0 repos · best confidence N/A
Best PoC traction
0
Maximum stars on a matched PoC repo

Why it matters now

Mention timeline

Total mentions
0
within the 30d window
Peak daily
0
highest bucket

Evidence

Source links by recency

Newest mentions first
3 source links · newest first

Exploit code

Public exploit repository references

Public PoC repositories are third-party, potentially unsafe artifacts. Treat their code as untrusted and use it only on authorized systems in an isolated, least-privilege environment. cvebuzz does not execute the code or verify that an exploit works.

0 repository references · best confidence N/A · max 0 stars
No public PoC repositories have been matched yet.

Related records

Similar CVEs

6 related CVEs with shared weakness or product evidence
  • CVE-2026-9679

    Impact: undici's cookie parser in parseSetCookie percent-decodes cookie values via qsUnescape, turning encoded sequences like %0D%0A, %00, %3B, and %3D into their literal byte equ…

    CVSS 5.9 · Medium
    2 mentions
  • CVE-2023-23936

    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 vulne…

    CVSS 6.5 · Medium
  • CVE-2022-35948

    undici is an HTTP/1.1 client, written from scratch for Node.js.`=< [email protected]` users are vulnerable to _CRLF Injection_ on headers when using unsanitized input as request header…

    CVSS 5.3 · Medium
  • CVE-2022-31150

    undici is an HTTP/1.1 client, written from scratch for Node.js. It is possible to inject CRLF sequences into request headers in undici in versions less than 5.7.1. A fix was relea…

    CVSS 5.3 · Medium
  • CVE-2026-44092

    An unauthenticated remote attacker can inject malicious input into the ModbusServer application because it does not validate the input it fetches from MQTT. This may lead to integ…

    CVSS 8.8 · High
    1 mention
  • CVE-2026-15157

    undici does not validate the type property of a duck-typed blob-like request body before using it as the Content-Type header on the HTTP/1.1 dispatcher. In undici before 6.28.0, f…

    CVSS 4.2 · Medium
    2 mentions