CVE-2026-45082: Karakeep SSRF Protection Bypass Flaw

CVE-2026-45082 Overview

CVE-2026-45082 is a Server-Side Request Forgery (SSRF) protection bypass vulnerability in Karakeep, a self-hostable bookmark-everything application. The flaw affects all versions prior to 0.32.0 and resides in redirect-following processing components. Although Karakeep implements protections to block requests targeting internal or private network destinations, attackers can bypass these controls using crafted HTTP redirect chains. Authenticated users can leverage attacker-controlled redirects to make the application reach internal Docker network services. The vulnerability impacts crawler functionality and video download processing flows. The maintainers addressed the issue in version 0.32.0. The weakness is classified under CWE-918.

Critical Impact
Authenticated attackers can pivot from Karakeep into adjacent Docker network services, exposing internal APIs and metadata endpoints that should be unreachable from external clients.

Affected Products

Karakeep versions prior to 0.32.0
Karakeep crawler processing component
Karakeep video download processing component

Discovery Timeline

2026-05-26 - CVE-2026-45082 published to NVD
2026-05-26 - Last updated in NVD database

Technical Details for CVE-2026-45082

Vulnerability Analysis

The vulnerability stems from incomplete SSRF protection in Karakeep's HTTP request handling. The application validates initial request destinations to block private and internal addresses. However, the protection logic does not re-evaluate destinations encountered during HTTP redirect chains. An authenticated user submits a URL pointing to an attacker-controlled host. That host returns an HTTP 3xx redirect targeting an internal address such as a Docker service name or RFC1918 IP. The Karakeep client follows the redirect without applying the same destination filtering, completing the request against the internal target.

This behavior affects multiple processing paths, including the crawler that fetches bookmark metadata and the video download flow that retrieves remote media. Both paths run server-side with network access to the container's internal Docker network. Successful exploitation reveals internal service responses to the attacker through application-rendered output or downstream processing artifacts.

Root Cause

The root cause is improper validation of redirect targets in HTTP fetcher components. Destination filtering occurs only on the initial user-supplied URL. Subsequent hops in a redirect chain inherit no validation, allowing redirection to internal hosts that the original policy would have rejected.

Attack Vector

An authenticated attacker submits a bookmark or video URL pointing to a host they control. That host issues a 302 redirect to an internal target such as http://localhost:9000, a Docker service hostname, or a cloud metadata endpoint. The crawler or downloader follows the redirect and contacts the internal service. The attacker observes content, behavior differences, or timing to enumerate and interact with internal services. See the Karakeep GitHub Security Advisory for details.

Detection Methods for CVE-2026-45082

Indicators of Compromise

Outbound HTTP requests from Karakeep containers redirected to RFC1918 ranges or Docker internal service names.
Crawler or video download jobs originating from URLs that return 3xx responses to internal hosts.
Unexpected access logs on internal services showing the Karakeep container as the client source.
Bookmark entries containing external domains that resolve through redirect chains to internal endpoints.

Detection Strategies

Inspect Karakeep application logs for redirect chains where the final destination differs from the user-submitted host.
Monitor egress traffic from the Karakeep container and alert on connections to internal subnets or metadata services such as 169.254.169.254.
Correlate authenticated user activity with crawler fetch events that target unusual response codes or internal hostnames.

Monitoring Recommendations

Enable verbose HTTP client logging in Karakeep to capture each hop of redirect chains.
Forward container network flow logs to a centralized analytics platform for retrospective hunting.
Alert on any traffic from the Karakeep container to ports associated with internal databases, admin consoles, or cloud metadata services.

How to Mitigate CVE-2026-45082

Immediate Actions Required

Upgrade Karakeep to version 0.32.0 or later on all self-hosted deployments.
Audit existing bookmarks and crawler queues for URLs pointing to suspicious external hosts.
Restrict authenticated account creation and review existing user accounts for anomalous activity.

Patch Information

Karakeep version 0.32.0 contains the patch that re-applies SSRF destination filtering to each hop in HTTP redirect chains across crawler and video download components. Refer to the Karakeep GitHub Security Advisory GHSA-g647-327m-79g9 for vendor guidance.

Workarounds

Place the Karakeep container in a network segment without route access to sensitive internal services or cloud metadata endpoints.
Apply egress firewall rules that deny outbound traffic from the Karakeep container to RFC1918 ranges and 169.254.169.254.
Disable crawler and video download functionality until the upgrade can be applied.

bash

# Example Docker Compose egress restriction using a dedicated network
networks:
  karakeep_isolated:
    driver: bridge
    internal: false
    driver_opts:
      com.docker.network.bridge.enable_ip_masquerade: "true"

services:
  karakeep:
    image: ghcr.io/karakeep-app/karakeep:0.32.0
    networks:
      - karakeep_isolated