high CVSS 8.6

CVE-2026-42595·Docker vulnerability

Gotenberg is a Docker-powered stateless API for PDF files. Prior to 8.32.0, Gotenberg's Chromium URL-to-PDF endpoint (/forms/chromium/convert/url) has no default protection against HTTP/HTTPS-based SSRF. The default deny-list regex only blocks file:// URIs. An unauthenticated attacker can point Chromium at any internal IP — including loopback, RFC 1918 ranges, and cloud metadata endpoints — and receive the response rendered as a PDF. Additionally, even when operators configure a custom deny-list, the protection is bypassed via HTTP redirects. Gotenberg's Chromium instance follows 302 redirects from an attacker-controlled external URL to internal targets without re-validating the redirect destination against the deny-list. This vulnerability is fixed in 8.32.0.

Severity: high
Software: Docker
Fixed in: 8.32.0
Published: 2026-05-14

Affected versions

Until: 8.32.0

Fixed in: 8.32.0

How to fix this CVE

Update Docker to version 8.32.0 or later to remediate CVE-2026-42595, which addresses Server-Side Request Forgery (SSRF) vulnerabilities in Gotenberg's Chromium URL-to-PDF conversion endpoint. The vulnerability allowed unauthenticated attackers to access internal services and cloud metadata endpoints by bypassing the default URI deny-list and exploiting HTTP redirect chains. Immediately apply this patch in environments where Gotenberg containers are exposed to untrusted network input.

sudo dnf update -y docker-ce && sudo systemctl restart docker

Defensia detects this vulnerability

What an exploitation attempt looks like

Sample log line indicative of exploitation attempts:

POST|GET /forms/chromium/convert/url.*(?:localhost|127\.0\.0\.1|10\.|172\.(1[6-9]|2[0-9]|3[01])\.|192\.168\.|169\.254\.|metadata\.google|169\.254\.169\.254).*Location:.*redirect

WAF mitigation (if patching is not yet possible)

Add this rule to your WAF to block exploitation attempts while you schedule the patch.

Implement a WAF rule to deny requests to /forms/chromium/convert/url containing URL parameters that reference private IP ranges (127.0.0.0/8, 10.0.0.0/8, 172.16.0.0/12, 192.168.0.0/16, 169.254.0.0/16) or cloud metadata endpoints (metadata.google, 169.254.169.254). Additionally, block responses containing HTTP Location headers that redirect to these ranges to prevent redirect-based bypass.

How to check if you are affected

Step 1: Check installed Docker version with `docker --version` and compare against 8.32.0
Step 2: List running Gotenberg containers with `docker ps | grep gotenberg` to identify exposed instances
Step 3: Search Docker daemon logs for suspicious /forms/chromium/convert/url requests: `journalctl -u docker -S '24 hours ago' | grep -i 'chromium\|convert/url'`
Step 4: After upgrading, verify the new version with `docker --version` and restart the Docker daemon with `sudo systemctl restart docker`

FAQ

What is CVE-2026-42595?

CVE-2026-42595 is a Server-Side Request Forgery (SSRF) vulnerability in Docker's Gotenberg service that allows unauthenticated attackers to abuse the Chromium PDF conversion API to reach internal services, cloud metadata endpoints, and private IP ranges by bypassing URI filtering and exploiting HTTP redirects.

Is CVE-2026-42595 being actively exploited?

According to CISA records, CVE-2026-42595 is not currently listed as actively exploited in the wild. However, no public exploit code is available, and the vulnerability remains high-severity due to its ease of exploitation and potential for lateral movement in containerized environments.

What versions of Docker are affected by CVE-2026-42595?

All versions of Docker containing Gotenberg prior to version 8.32.0 are affected. The vulnerability requires explicit use of the Chromium URL-to-PDF endpoint, so exposure depends on whether your Gotenberg instance is reachable from untrusted networks.

How do I check if my server is vulnerable to CVE-2026-42595?

Run `docker --version` to confirm your Docker version is below 8.32.0. Then verify Gotenberg is running with `docker ps --filter 'name=gotenberg'`. If the service is exposed and Docker is outdated, your environment is vulnerable.

Does Defensia detect CVE-2026-42595?

Yes — Defensia's CVE advisory scanner compares installed package versions against the NVD database. If Docker is installed on a monitored server, CVE-2026-42595 will appear in your dashboard with remediation steps.

Related Docker CVEs

CVE-2026-40281CVSS 10Gotenberg is a Docker-powered stateless API for PDF files. In versions 8.30.1 and earlier, the metadata write endpoint validates metadata keys for control characters but leaves metadata values unsanitized. A newline character in a metadata value splits the ExifTool stdin line into two separate arguments, allowing injection of arbitrary ExifTool pseudo-tags such as -FileName, -Directory, -SymLink, and -HardLink. This is a bypass of the incomplete key-sanitization fix introduced in v8.30.1. An unauthenticated attacker can rename or move any PDF being processed to an arbitrary path in the container filesystem, overwrite arbitrary files, or create symlinks and hard links at arbitrary paths.

CVE-2026-53576CVSS 10Kestra is an open-source, event-driven orchestration platform. Prior to 1.0.45 and 1.3.21, the authentication filter for the REST API (@Filter("/api/v1/**")) treats any request whose path ends in /configs as the public instance-config endpoint and forwards it without a credential check. kestra addresses its resources by URL path segments that the caller chooses (/api/v1/{tenant}/flows/{namespace}, /api/v1/{tenant}/executions/{namespace}/{id}, /api/v1/{tenant}/namespaces/{namespace}/kv/{key}). An anonymous caller picks the literal configs as the final segment, and the request bypasses Basic-Auth entirely. Because the bypass reaches the flow-create and execution-trigger routes, an unauthenticated caller creates a flow containing a Shell or Process task and runs it. The task executes as root inside the kestra container. The official docker-compose.yml mounts /var/run/docker.sock, so root in the container reaches the host Docker daemon. This vulnerability is fixed in 1.0.45 and 1.3.21.

CVE-2026-26216CVSS 10Crawl4AI versions prior to 0.8.0 contain a remote code execution vulnerability in the Docker API deployment. The /crawl endpoint accepts a hooks parameter containing Python code that is executed using exec(). The __import__ builtin was included in the allowed builtins, allowing unauthenticated remote attackers to import arbitrary modules and execute system commands. Successful exploitation allows full server compromise, including arbitrary command execution, file read and write access, sensitive data exfiltration, and lateral movement within internal networks.

CVE-2026-44329CVSS 10free5GC is an open-source implementation of the 5G core network. Prior to 4.2.2, free5GC's SMF mounts the UPI management route group without OAuth2/bearer-token authorization middleware. A network attacker who can reach SMF on the SBI can hit UPI endpoints with no Authorization header at all, and the requests reach the SMF business handlers. In the running Docker lab this was directly demonstrated for read (GET /upi/v1/upNodesLinks), write (POST /upi/v1/upNodesLinks with attacker-controlled UP-node and link payload), and delete (DELETE /upi/v1/upNodesLinks/{nodeID}) operations. This vulnerability is fixed in 4.2.2.

CVE-2026-33587CVSS 10Lack of user input sanitisation in Open Notebook v1.8.3 allows the application user to execute Python code (and subsequently OS commands) on the docker container via Server-Side Template Injection (SSTI) for user-created transformations.

References

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