What is the CVSS score of CVE-2026-0858?

CVE-2026-0858 has a CVSS 4.0 base score of 2.0 (Low). CVSS vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:L/VA:N/SC:L/SI:L/SA:N/E:P. EPSS exploitation probability: 0.0%.

How to fix or mitigate CVE-2026-0858?

Within 30 days: Identify affected systems and apply vendor patches as part of regular patch cycle. Verify Content-Security-Policy and output encoding.

Plantuml CVE-2026-0858

LOW

Cross-site Scripting (XSS) (CWE-79)

2026-01-16 report@snyk.io

GHSA-hrvf-g648-rf3m

XSS Plantuml

2.0

CVSS 4.0 · NVD

View

Vulnerability Assessment

Weakness	CWE CWE-79 OWASP Top 10:2025 A05:2025 - Injection ASVS 5.0 V1 - Encoding and Sanitization Output encoding, context-aware escaping MITRE ATT&CK 2 techniques across 2 tactics: Initial Access, Execution The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up. Sign in to read
Impact	CVSS 6.1 (MEDIUM). Attack vector: Network. Complexity: Low. Privileges required: None. User interaction: Required.
Exploit ScenarioDerived	An attacker could exploit this flaw, arbitrary script execution in the context of applications th.

Monitor Track and reassess. Why: LOW severity (CVSS 0.1-3.9).

Patch available 0.0% exploitation probability (EPSS)

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AnalysisAIv1 – Mar 12, 2026

PlantUML versions before 1.2026.0 fail to properly sanitize interactive attributes in GraphViz diagrams, allowing attackers to inject malicious JavaScript into SVG output through crafted diagram files. Applications that render these SVGs are vulnerable to arbitrary script execution within the user's browser context. A patch is available to address this stored XSS vulnerability.

Earlier versions of this analysis (1)

v1 Mar 12, 2026 - 21:54 CVSS 6.1

RemediationAI

A vendor patch is available — apply it immediately. Implement output encoding and Content Security Policy headers. Restrict network access to the affected service where possible.

Affected Packages

maven net.sourceforge.plantuml:plantuml fix: 1.2026.0

Source: OSV (Open Source Vulnerabilities)

Affects your stack

Affects 1 package in maven

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

Classified as CWE-79 (Cross-site Scripting (XSS)). Affects Plantuml. Versions of the package net.sourceforge.plantuml:plantuml before 1.2026.0 are vulnerable to Stored XSS due to insufficient sanitization of interactive attributes in GraphViz diagrams. As a result, a crafted PlantUML diagram can inject malicious JavaScript into generated SVG output, leading to arbitrary script execution in the context of applications that render the SVG.

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Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

NVD PRIMARY 2.0 LOW

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:L/VA:N/SC:L/SI:L/SA:N/E:P

SUSE 6.1 MEDIUM

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

Red Hat 6.1 MEDIUM

Primary rating from NVD.

CVSS VectorNVD

Attack Vector

Network

Attack Complexity

Low

Attack Requirements

None

Privileges Required

None

User Interaction

Active

Vulnerable system: Confidentiality

None

Vulnerable system: Integrity

Low

Vulnerable system: Availability

None

Subsequent system: Confidentiality

Low

Subsequent system: Integrity

Low

Subsequent system: Availability

None

Lifecycle Timeline

Severity Changed

Apr 29, 2026 - 01:11 NVD

MEDIUM LOW

CVSS changed

Apr 29, 2026 - 01:11 NVD

6.1 (MEDIUM) 2.0 (LOW)

Patch released

Feb 02, 2026 - 18:52 nvd

Patch available

CVE Published

Jan 16, 2026 - 05:16 nvd

MEDIUM 6.1

DescriptionCVE.org

Versions of the package net.sourceforge.plantuml:plantuml before 1.2026.0 are vulnerable to Stored XSS due to insufficient sanitization of interactive attributes in GraphViz diagrams. As a result, a crafted PlantUML diagram can inject malicious JavaScript into generated SVG output, leading to arbitrary script execution in the context of applications that render the SVG.

Executive ViewAI

Why It Matters

CVE-2026-0858 presents moderate security risk, a cross-site scripting vulnerability rated CVSS 6.1. Attackers could inject scripts to steal sessions or perform actions as authenticated users. A patch is available and should be applied during regular vulnerability management.

Business Impact: Low

Compensating Controls

Apply vendor patch. If patching is delayed: implement CSP headers, enable HttpOnly cookies, deploy WAF XSS rules.

Threat Intelligence Overview

EPSS Score

0.0%

Top 98% exploitable

Data Quality

5 sources

Confidence: Medium

NVD

CVE.org

EPSS Vendor

GitHub

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue

Severity LOW

CISA KEV No

Public POC No

EPSS 0.0%

Patch available Yes

Active threat No

Deciding rule

LOW severity (CVSS 0.1-3.9)

What every action level means

Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.

Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.

This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.

This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.

Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.