How severe is CVE-2026-9520?

CVE-2026-9520 has a CVSS 3.x base score of 4.3, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is none, integrity low, and availability none.

Is CVE-2026-9520 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (26th percentile), an estimate of the probability of exploitation in the next 30 days.

How do I fix CVE-2026-9520?

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

Does CVE-2026-9520 have an EU (EUVD) identifier?

Yes. CVE-2026-9520 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-31781.

When was CVE-2026-9520 published?

CVE-2026-9520 was published on 2026-05-26 and last updated on 2026-06-17.

CVE-2026-9520

CVE-2026-9520 is a medium-severity vulnerability with a CVSS 3.x base score of 4.3. 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 4.3)
CVSS v2: 5.0
CVSS v4: 2.1
EPSS exploit prediction: 0% (26th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-31781
Weakness: CWE-79
Published: 2026-05-26
Last modified: 2026-06-17

Description

A weakness has been identified in blitz-js blitz up to 3.0.2 on GitHub. This impacts an unknown function of the file packages/generator/templates/app/src/app/auth/components/LoginForm.tsx of the component Sign-in. This manipulation of the argument Next causes cross site scripting. It is possible to initiate the attack remotely. The exploit has been made available to the public and could be used for attacks. The vendor was contacted early about this disclosure but did not respond in any way.

Frequently asked questions

What is CVE-2026-9520?: A weakness has been identified in blitz-js blitz up to 3.0.2 on GitHub. This impacts an unknown function of the file packages/generator/templates/app/src/app/auth/components/LoginForm.tsx of the component Sign-in. This manipulation of the argument Next causes cross site scripting. It is possible to initiate the attack remotely. The exploit has been made available to the public and could be used for attacks. The vendor was contacted early about this disclosure but did not respond in any way.
How severe is CVE-2026-9520?: CVE-2026-9520 has a CVSS 3.x base score of 4.3, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is none, integrity low, and availability none.
Is CVE-2026-9520 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (26th percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2026-9520?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2026-9520 have an EU (EUVD) identifier?: Yes. CVE-2026-9520 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-31781.
When was CVE-2026-9520 published?: CVE-2026-9520 was published on 2026-05-26 and last updated on 2026-06-17.

References

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

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