VulnerabilityPublished 6 Nov 2026

CVE-2026-102356: yuzutech kroki · Server-Side Request Forgery

Affects yuzutech krokiSource CVE Database V5

Compare

Not known to be exploited · CVSS 5.0 Medium : upgrade to 0.31.2 when convenient.

Data as of 6 Nov 2026, 17:55 UTC

CVSS 3.1 base score

5.0Medium

How severe the flaw is on the 0–10 CVSS scale.

Thin evidence

One scorer or none

CVSS scores by source
CNA (GitHub_M)	CVSS 3.1	5.0

Patch: Available – fixed in 0.31.2

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

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

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: Low: The attacker is authorized with (i.e., requires) privileges that provide basic user capabilities that could normally affect only settings and files owned by a user. Alternatively, an attacker with Low privileges may have the ability to cause an impact only to non-sensitive resources.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Changed: An exploited vulnerability can affect resources beyond the security scope managed by the security authority of the vulnerable component. In this case, the vulnerable component and the impacted component are different and managed by different security authorities.
Confidentiality: Low: There is some loss of confidentiality. Access to some restricted information is obtained, but the attacker does not have control over what information is obtained, or the amount or kind of loss is limited. The information disclosure does not cause a direct, serious loss to the impacted component.
Integrity: None: There is no loss of integrity within the impacted component.
Availability: None: There is no impact to availability within the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 6 Nov 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 6 Nov 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade yuzutech kroki to 0.31.2.

Affected software

Product	Affected	Fixed in
yuzutechkroki	Affected >=0.26.0 <0.31.2	Fixed in 0.31.2

AI-suggested

Upgrade Kroki to version 0.31.2 or later, where this SSRF vulnerability is fixed. No additional mitigations are indicated by the vendor advisory. If upgrading is not immediately possible, restrict access to the Mermaid companion and diagram submission interfaces to trusted users only, and ensure network segmentation limits the companion's ability to reach sensitive internal resources.

Description

Kroki versions from 0.26.0 up to but not including 0.31.2 contain a server-side request forgery (SSRF) vulnerability in the Mermaid companion's PNG rendering process. This flaw allows an authenticated actor who can submit Mermaid source diagrams to cause the companion to issue HTTP or HTTPS GET requests without network request restrictions, even when safe mode is enabled. The vulnerability is fixed in version 0.31.2.

Impact

An authenticated user with permission to submit Mermaid diagrams can cause Kroki's Mermaid companion to make arbitrary HTTP/HTTPS GET requests from the server hosting the companion. This can lead to blind SSRF, potentially triggering state changes on reachable endpoints. However, there is no confirmed impact involving data exfiltration, cloud metadata access, or broader network scanning. The vulnerability does not affect confidentiality or availability directly but may allow limited unauthorized network interactions.

Summary

Kroki's Mermaid companion (mermaid/src/worker.js) in versions >=0.26.0 <0.31.2 renders attacker-controlled flowchart image nodes using headless Chromium without enforcing a network request policy, despite KROKI_SAFE_MODE being set. An authenticated actor able to submit Mermaid source diagrams can trigger HTTP/HTTPS GET requests during PNG rendering. Exploitation requires the Mermaid companion, PNG rendering via headless Chromium, a diagram submission path accessible to the actor, and network reachability from the companion to the target. The impact is limited to blind request reachability and potential state-changing GET endpoints; no evidence supports response exfiltration, cloud metadata access, port scanning, or access beyond the companion's network reachability. The issue is resolved in Kroki version 0.31.2.

CWE-918Server-Side Request Forgery (opens in a new tab)
Base weaknessCWE Top 25 (2025): #22OWASP Top 10 A01:2025: Broken Access Control (opens in a new tab)
The web server receives a URL or similar request from an upstream component and retrieves the contents of this URL, but it does not sufficiently ensure that the request is being sent to the expected destination.
Implementation · Operation
If there is a known list of applications, IP, hostname, and/or domains to which the product is allowed to communicate, then use allowlists to ensure that outgoing requests are restricted to these known entities. The allowlists could be in the application code or possibly enforced by firewalls or network segmentation.
Implementation · Operation
If the product is expected to be able to connect to arbitrary IP addresses or domains, consider using a denylist that includes private network addresses, internal domain names, etc. The denylist could be in the application code or possibly enforced by firewalls or network segmentation.
Implementation · Input Validation
Assume all input is malicious. Use an "accept known good" input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does.
OWASP Cheat Sheets
Server Side Request Forgery Prevention (opens in a new tab)
Unvalidated Redirects and Forwards (opens in a new tab)
Cross Site Scripting Prevention (opens in a new tab)
DOM based XSS Prevention (opens in a new tab)
Authorization (opens in a new tab)
OWASP ASVS 4.0.3
V12.6.1 (opens in a new tab)
V5.2.6 (opens in a new tab)
Attack patterns
Server Side Request Forgery (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

Community reviews

Loading reviews…

Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 6 Nov 2026, 17:55 UTC

WeaknessesCWE-918

Technical details

References

Community reviews

Related threats