How severe is CVE-2026-40922?

CVE-2026-40922 has a CVSS 3.x base score of 5.4, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and user interaction. Impact on confidentiality is low, integrity low, and availability none.

Is CVE-2026-40922 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (17th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-40922?

CVE-2026-40922 affects B3log Siyuan. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-40922?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

Does CVE-2026-40922 have an EU (EUVD) identifier?

Yes. CVE-2026-40922 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-23331.

When was CVE-2026-40922 published?

CVE-2026-40922 was published on 2026-04-17 and last updated on 2026-06-17.

CVE-2026-40922

CVE-2026-40922 is a medium-severity vulnerability in B3log Siyuan with a CVSS 3.x base score of 5.4. 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: Medium (CVSS 3.x base score 5.4)
CVSS v4: 5.3
EPSS exploit prediction: 0% (17th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-23331
Weakness: CWE-79
Affected product: B3log Siyuan
Published: 2026-04-17
Last modified: 2026-06-17

Description

SiYuan is an open-source personal knowledge management system. In versions 3.6.1 through 3.6.3, a prior fix for XSS in bazaar README rendering (incomplete fix for CVE-2026-33066) enabled the Lute HTML sanitizer, but the sanitizer does not block iframe tags, and its URL-prefix blocklist does not effectively filter srcdoc attributes which contain raw HTML rather than URLs. A malicious bazaar package author can include an iframe with a srcdoc attribute containing embedded scripts in their README. When other users view the package in SiYuan's marketplace UI, the payload executes in the Electron context with full application privileges, enabling arbitrary code execution on the user's machine. This issue has been fixed in version 3.6.4.

Frequently asked questions

What is CVE-2026-40922?: SiYuan is an open-source personal knowledge management system. In versions 3.6.1 through 3.6.3, a prior fix for XSS in bazaar README rendering (incomplete fix for CVE-2026-33066) enabled the Lute HTML sanitizer, but the sanitizer does not block iframe tags, and its URL-prefix blocklist does not effectively filter srcdoc attributes which contain raw HTML rather than URLs. A malicious bazaar package author can include an iframe with a srcdoc attribute containing embedded scripts in their README. When other users view the package in SiYuan's marketplace UI, the payload executes in the Electron context with full application privileges, enabling arbitrary code execution on the user's machine. This issue has been fixed in version 3.6.4.
How severe is CVE-2026-40922?: CVE-2026-40922 has a CVSS 3.x base score of 5.4, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and user interaction. Impact on confidentiality is low, integrity low, and availability none.
Is CVE-2026-40922 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (17th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-40922?: CVE-2026-40922 affects B3log Siyuan. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-40922?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2026-40922 have an EU (EUVD) identifier?: Yes. CVE-2026-40922 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-23331.
When was CVE-2026-40922 published?: CVE-2026-40922 was published on 2026-04-17 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:b3log:siyuan:*:*:*:*:*:*:*:*

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