Kroki Mermaid companion SSRF via flowchart image URLs

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-102356
StatePUBLISHED
AssignerGitHub_M
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-11-06 18:17:36 UTC
Updated2026-11-06 18:17:36 UTC
DescriptionKroki creates diagrams from textual descriptions. From 0.26.0 until 0.31.2, the optional Mermaid companion's mermaid/src/worker.js renders attacker-controlled flowchart image nodes in headless Chromium without a network request policy, even when KROKI_SAFE_MODE is set to secure. An actor who can submit Mermaid source and satisfy any authentication or authorization configured by the deployment can cause the companion to issue HTTP or HTTPS GET requests when requesting PNG output. Exploitation requires the Mermaid companion, PNG rendering through its headless Chromium process, a diagram-submission path available to the actor, and network reachability from the companion to the target. The demonstrated impact is limited to blind request reachability and possible state-changing GET endpoints; response exfiltration, cloud metadata access, port scanning, and access beyond the companion's network reachability are not established. This issue is fixed in version 0.31.2.

Risk And Classification

Primary CVSS: v3.1 5 MEDIUM from [email protected]

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:N/A:N

Problem Types: CWE-918 | CWE-918 CWE-918: Server-Side Request Forgery (SSRF)

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary5MEDIUMCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:N/A:N
3.1CNADECLARED5MEDIUMCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:N/A:N

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Changed
Confidentiality
Low
Integrity
None
Availability
None

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:N/A:N

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Yuzutech Kroki affected >= 0.26.0, < 0.31.2 Not specified

References

ReferenceSourceLinkTags
github.com/yuzutech/kroki/commit/428ea380bc7db9da5c7947f908851c8461d51f82 [email protected] github.com
github.com/yuzutech/kroki/releases/tag/v0.31.2 [email protected] github.com
github.com/yuzutech/kroki/security/advisories/GHSA-px99-rjv4-49g8 [email protected] github.com
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