How severe is CVE-2026-56397?

CVE-2026-56397 has a CVSS 3.x base score of 9.6, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2026-56397 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (31st percentile), an estimate of the probability of exploitation in the next 30 days.

How do I fix CVE-2026-56397?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

Does CVE-2026-56397 have an EU (EUVD) identifier?

Yes. CVE-2026-56397 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-38163.

When was CVE-2026-56397 published?

CVE-2026-56397 was published on 2026-06-21 and last updated on 2026-06-24.

CVE-2026-56397

CVE-2026-56397 is a critical-severity vulnerability with a CVSS 3.x base score of 9.6. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-79.

Key facts

Severity: Critical (CVSS 3.x base score 9.6)
CVSS v4: 9.4
EPSS exploit prediction: 0% (31st percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-38163
Weakness: CWE-79
Published: 2026-06-21
Last modified: 2026-06-24

Description

SiYuan before v3.6.1 fails to sanitize package metadata and README content in the Bazaar marketplace, allowing malicious package authors to inject arbitrary HTML and JavaScript. Attackers can achieve remote code execution on any user browsing the Bazaar by embedding XSS payloads in package displayName, description, or README fields, exploiting Electron's nodeIntegration setting to execute OS commands.

Frequently asked questions

What is CVE-2026-56397?: SiYuan before v3.6.1 fails to sanitize package metadata and README content in the Bazaar marketplace, allowing malicious package authors to inject arbitrary HTML and JavaScript. Attackers can achieve remote code execution on any user browsing the Bazaar by embedding XSS payloads in package displayName, description, or README fields, exploiting Electron's nodeIntegration setting to execute OS commands.
How severe is CVE-2026-56397?: CVE-2026-56397 has a CVSS 3.x base score of 9.6, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2026-56397 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (31st percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2026-56397?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
Does CVE-2026-56397 have an EU (EUVD) identifier?: Yes. CVE-2026-56397 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-38163.
When was CVE-2026-56397 published?: CVE-2026-56397 was published on 2026-06-21 and last updated on 2026-06-24.

References

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

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CVE-2024-6886 — Critical (CVSS 10.0): Improper Neutralization of Input During Web Page Generation (XSS or 'Cross-site Scripting') vulnerability in Gitea…
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CVE-2023-45138 — Critical (CVSS 10.0): Change Request is an pplication allowing users to request changes on a wiki without publishing the changes directly.…
CVE-2022-4361 — Critical (CVSS 10.0): Keycloak, an open-source identity and access management solution, has a cross-site scripting (XSS) vulnerability in the…

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