How severe is CVE-2026-34429?

CVE-2026-34429 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-2026-34429 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (20th percentile), an estimate of the probability of exploitation in the next 30 days.

How do I fix CVE-2026-34429?

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

Does CVE-2026-34429 have an EU (EUVD) identifier?

Yes. CVE-2026-34429 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-23854.

When was CVE-2026-34429 published?

CVE-2026-34429 was published on 2026-04-20 and last updated on 2026-06-17.

CVE-2026-34429

CVE-2026-34429 is a medium-severity vulnerability 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: 5.1
EPSS exploit prediction: 0% (20th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-23854
Weakness: CWE-79
Published: 2026-04-20
Last modified: 2026-06-17

Description

Vvveb prior to 1.0.8.1 contains a stored cross-site scripting vulnerability that allows authenticated users with media upload and rename permissions to execute arbitrary JavaScript by bypassing MIME type validation and renaming uploaded files to executable extensions. Attackers can prepend a GIF89a header to HTML/JavaScript payloads to bypass upload validation, rename the file to .html extension, and execute malicious scripts in an administrator's browser session to create backdoor accounts and upload malicious plugins for remote code execution.

Frequently asked questions

What is CVE-2026-34429?: Vvveb prior to 1.0.8.1 contains a stored cross-site scripting vulnerability that allows authenticated users with media upload and rename permissions to execute arbitrary JavaScript by bypassing MIME type validation and renaming uploaded files to executable extensions. Attackers can prepend a GIF89a header to HTML/JavaScript payloads to bypass upload validation, rename the file to .html extension, and execute malicious scripts in an administrator's browser session to create backdoor accounts and upload malicious plugins for remote code execution.
How severe is CVE-2026-34429?: CVE-2026-34429 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-2026-34429 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (20th percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2026-34429?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2026-34429 have an EU (EUVD) identifier?: Yes. CVE-2026-34429 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-23854.
When was CVE-2026-34429 published?: CVE-2026-34429 was published on 2026-04-20 and last updated on 2026-06-17.

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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