How severe is CVE-2026-30226?

CVE-2026-30226 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2026-30226 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (29th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-30226?

CVE-2026-30226 affects Svelte Devalue. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-30226?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

Does CVE-2026-30226 have an EU (EUVD) identifier?

Yes. CVE-2026-30226 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-11253.

When was CVE-2026-30226 published?

CVE-2026-30226 was published on 2026-03-11 and last updated on 2026-06-17.

CVE-2026-30226

CVE-2026-30226 is a high-severity vulnerability in Svelte Devalue with a CVSS 3.x base score of 7.5. 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-1321.

Key facts

Severity: High (CVSS 3.x base score 7.5)
CVSS v4: 6.3
EPSS exploit prediction: 0% (29th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-11253
Weakness: CWE-1321
Affected product: Svelte Devalue
Published: 2026-03-11
Last modified: 2026-06-17

Description

Svelte devalue is a JavaScript library that serializes values into strings when JSON.stringify isn't sufficient for the job. In devalue v5.6.3 and earlier, devalue.parse and devalue.unflatten were susceptible to prototype pollution via maliciously crafted payloads. Successful exploitation could lead to Denial of Service (DoS) or type confusion. This vulnerability is fixed in 5.6.4.

Frequently asked questions

What is CVE-2026-30226?: Svelte devalue is a JavaScript library that serializes values into strings when JSON.stringify isn't sufficient for the job. In devalue v5.6.3 and earlier, devalue.parse and devalue.unflatten were susceptible to prototype pollution via maliciously crafted payloads. Successful exploitation could lead to Denial of Service (DoS) or type confusion. This vulnerability is fixed in 5.6.4.
How severe is CVE-2026-30226?: CVE-2026-30226 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2026-30226 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (29th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-30226?: CVE-2026-30226 affects Svelte Devalue. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-30226?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2026-30226 have an EU (EUVD) identifier?: Yes. CVE-2026-30226 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-11253.
When was CVE-2026-30226 published?: CVE-2026-30226 was published on 2026-03-11 and last updated on 2026-06-17.

References

https://github.com/sveltejs/devalue/security/advisories/GHSA-cfw5-2vxh-hr84

Affected products (1)

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

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