How severe is CVE-2026-27902?

CVE-2026-27902 has a CVSS 3.x base score of 5.4, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is low, integrity low, and availability none.

Is CVE-2026-27902 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (13th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-27902?

CVE-2026-27902 affects Svelte. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-27902?

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

Does CVE-2026-27902 have an EU (EUVD) identifier?

Yes. CVE-2026-27902 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-8800.

When was CVE-2026-27902 published?

CVE-2026-27902 was published on 2026-02-26 and last updated on 2026-06-17.

CVE-2026-27902

CVE-2026-27902 is a medium-severity vulnerability in Svelte 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% (13th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-8800
Weakness: CWE-79
Affected product: Svelte
Published: 2026-02-26
Last modified: 2026-06-17

Description

Svelte performance oriented web framework. Prior to version 5.53.5, errors from `transformError` were not correctly escaped prior to being embedded in the HTML output, causing potential HTML injection and XSS if attacker-controlled content is returned from `transformError`. Version 5.53.5 fixes the issue.

Frequently asked questions

What is CVE-2026-27902?: Svelte performance oriented web framework. Prior to version 5.53.5, errors from `transformError` were not correctly escaped prior to being embedded in the HTML output, causing potential HTML injection and XSS if attacker-controlled content is returned from `transformError`. Version 5.53.5 fixes the issue.
How severe is CVE-2026-27902?: CVE-2026-27902 has a CVSS 3.x base score of 5.4, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is low, integrity low, and availability none.
Is CVE-2026-27902 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (13th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-27902?: CVE-2026-27902 affects Svelte. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-27902?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2026-27902 have an EU (EUVD) identifier?: Yes. CVE-2026-27902 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-8800.
When was CVE-2026-27902 published?: CVE-2026-27902 was published on 2026-02-26 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:svelte:svelte:*:*:*:*:*:node.js:*:*

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