CVE-2026-73247: Kestra Server-Side Request Forgery via Pebble http() function

CVE-2026-73247 · Severity: high · CVSS 8.6 · Published 2026-08-11

Kestra, an open-source workflow orchestration platform, contains a vulnerability in its Pebble template engine that allows attackers to make arbitrary HTTP requests to internal services and cloud metadata endpoints without authentication. An attacker can import a malicious workflow and retrieve sensitive cloud credentials (AWS/GCP/Azure), access internal services, or interact with localhost endpoints, potentially leading to credential theft and lateral movement within cloud environments.

Technologies: Kestra. Vendors: Kestra, Maven.

Quick answers

Is CVE-2026-73247 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2026-73247 being exploited in the wild.
How severe is CVE-2026-73247?
High severity, with a CVSS score of 8.6, published 11 August 2026.
Which products and versions are affected?
Kestra all versions (OSS); io.kestra:core (Maven) <= 1.3.31, ECOSYSTEM:introduced=0,last_affected=1.3.31; io.kestra:kestra-core (Maven) < 2.0.0, ECOSYSTEM:introduced=0,fixed=2.0.0.
Is there a fix for CVE-2026-73247?
Yes. io.kestra:kestra-core (Maven): upgrade to 2.0.0 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-73247 attacked?
It is attacked over the network.
Am I affected by CVE-2026-73247?
Check whether you run Kestra, io.kestra:core (Maven) or io.kestra:kestra-core (Maven) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

  • io.kestra:kestra-core (Maven): upgrade to 2.0.0 or later
    # set io.kestra:kestra-core to 2.0.0 in your pom.xml or build.gradle

Technical details

The vulnerability is a Server-Side Request Forgery (SSRF) in the Pebble template engine's http() function (HttpFunction.java, lines 77–106). The root cause is the lack of URL validation: user-supplied URLs are passed directly to URI.create() without checks for private IP ranges (10.0.0.0/8, 192.168.0.0/16, 127.0.0.1), cloud metadata endpoints (169.254.169.254), or restricted URL schemes (file://, gopher://). Additionally, no authentication is enforced beyond a basic tenant check for "main", and the HttpFunction is unconditionally registered. An unauthenticated attacker can import a malicious workflow YAML file and execute it to trigger HTTP requests from the server, bypassing network perimeter controls to access internal systems and metadata services.

Affected products

  • Kestra Kestra all versions (OSS)

Identifiers

  • CVE-2026-73247
  • GHSA-r56g-q4p6-m3p6

Timeline

  • 2026-09-17: disclosed: Advisory GHSA-r56g-q4p6-m3p6 published

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