7.5

CVE-2026-30226: devalue has prototype pollution in devalue.parse and devalue.unflatten

Analyzed
AliasesGHSA-cfw5-2vxh-hr84
Published 11-03-2026Last modified 12-03-2026

Vulnerability summary

CVE-2026-30226 is a high (CVSS 7.5) vulnerability in svelte devalue. EPSS estimates a 0.42% chance of exploitation in the next 30 days, higher than 35.9% of scored vulnerabilities.

Priority
Routine

Not severe (CVSS 6.3, network access); no exploitation reported by the 5 checked sources

Source freshness unavailable

How is this decided?
CVSS score
7.5/10
010
High · v3.1 (NVD)
EPSS score
0.42%
0%100%
Low · -0.08 pp in 30 days
KEVNot listedNot listed by any tracked catalog.
RansomwareNot flaggedNo ransomware use recorded.
Public exploits0No public exploits recorded

Timeline

  1. 11-03-2026
    PublishedVulnerability first disclosed.
  2. 12-03-2026
    Last modifiedVulnerability information updated.

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.

CVSS metrics

4 scores · 3 sources · 2 versions

EPSS trend

Probability

0.42%

Chance of exploitation in the next 30 days

Percentile

36%

Versus all other CVEs

30-day change

Decrease -0.08 pp

From 0.50% on 04-10-2026

04-10-202603-11-2026

Known exploited

Compare KEV catalogs
CISA KEV

Not in the CISA KEV catalog.

ENISA CNW

Not in the ENISA CNW catalog.

CIRCL

Not in the CIRCL catalog.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Version check

Known conditions: network-reachable, no authentication, no user interaction (CVSS vector). Other conditions: not stated in public data.

Npm1 product
  • devalue< 5.6.4
Svelte1 product
Sveltejs1 product

3 vendors · 3 products

References

3 links