CVE-2026-59791Network attack vector

CSS injection via Mermaid diagram rendering

Published Jul 10, 2026 · Updated Jul 10, 2026

CSS injection in JetBrains YouTrack before 2026.2.17012 allows remote authenticated users to modify rendered content through Mermaid diagrams. JetBrains identifies Mermaid diagram rendering as the vector but has not disclosed the affected renderer locus or the validation operation that permits CSS. Low-privileged access and viewer interaction are required; the published impact is limited to rendered-content modification.

CVSS severity3.5
Low
EPSS probability0.23%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

CSS injection in JetBrains YouTrack before 2026.2.17012 allows remote authenticated users to modify rendered content through Mermaid diagrams. JetBrains identifies Mermaid diagram rendering as the vector but has not disclosed the affected renderer locus or the validation operation that permits CSS. Low-privileged access and viewer interaction are required; the published impact is limited to rendered-content modification.

The record

CVE
CVE-2026-59791
Published
Jul 10, 2026
Updated
Jul 10, 2026
Vendor
JetBrains
Product
YouTrack
Classifications
CWE-1021
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jul 10, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 10, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <2026.2.17012

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

JetBrains · YouTrackversion=0 <2026.2.17012

Published CVSS scores

3.5JetBrains s.r.o.CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:L/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-1021Improper Restriction of Rendered UI Layers or Frames

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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