How severe is CVE-2026-42159?

CVE-2026-42159 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-2026-42159 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (9th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-42159?

CVE-2026-42159 affects Flowsint. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-42159?

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

Does CVE-2026-42159 have an EU (EUVD) identifier?

Yes. CVE-2026-42159 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-30308.

When was CVE-2026-42159 published?

CVE-2026-42159 was published on 2026-05-14 and last updated on 2026-06-17.

CVE-2026-42159

CVE-2026-42159 is a medium-severity vulnerability in Flowsint 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% (9th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-30308
Weakness: CWE-79
Affected product: Flowsint
Published: 2026-05-14
Last modified: 2026-06-17

Description

Flowsint is an open-source OSINT graph exploration tool designed for cybersecurity investigation, transparency, and verification. Prior to 1.2.3, Flowsint allows a user to create investigations, which are used to manage sketches and analyses. Sketches have controllable graphs, which are comprised of nodes and relationships. The sketches contain information on an OSINT target (usernames, websites, etc) within these nodes and relationships. A remote attacker can create a node with a malicious description that contains arbitrary HTML. When the node is selected, it will render the arbitrary HTML, potentially triggering stored XSS. This vulnerability is fixed in 1.2.3.

Frequently asked questions

What is CVE-2026-42159?: Flowsint is an open-source OSINT graph exploration tool designed for cybersecurity investigation, transparency, and verification. Prior to 1.2.3, Flowsint allows a user to create investigations, which are used to manage sketches and analyses. Sketches have controllable graphs, which are comprised of nodes and relationships. The sketches contain information on an OSINT target (usernames, websites, etc) within these nodes and relationships. A remote attacker can create a node with a malicious description that contains arbitrary HTML. When the node is selected, it will render the arbitrary HTML, potentially triggering stored XSS. This vulnerability is fixed in 1.2.3.
How severe is CVE-2026-42159?: CVE-2026-42159 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-2026-42159 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (9th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-42159?: CVE-2026-42159 affects Flowsint. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-42159?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2026-42159 have an EU (EUVD) identifier?: Yes. CVE-2026-42159 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-30308.
When was CVE-2026-42159 published?: CVE-2026-42159 was published on 2026-05-14 and last updated on 2026-06-17.

References

https://github.com/reconurge/flowsint/security/advisories/GHSA-w233-5mmx-cr7x

Affected products (1)

cpe:2.3:a:flowsint:flowsint:*:*:*:*:*:*:*:*

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