CVE-2026-1527 Affecting langfuse-3 package, versions <3.179.1-r1


Severity

Recommended
low

Based on default assessment until relevant scores are available.

Threat Intelligence

EPSS
0.28% (20th percentile)

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  • Snyk IDSNYK-CHAINGUARDLATEST-LANGFUSE3-17239473
  • published9 Jun 2026
  • disclosed12 Mar 2026

Introduced: 12 Mar 2026

CVE-2026-1527  (opens in a new tab)

How to fix?

Upgrade Chainguard langfuse-3 to version 3.179.1-r1 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream langfuse-3 package and not the langfuse-3 package as distributed by Chainguard. See How to fix? for Chainguard relevant fixed versions and status.

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 Base Scores

version 3.1