CVE-2026-123565

Devalue before 5.9.3 Quadratic Expansion Denial of Service via uneval

CVSS 4.0 8.7 HIGHCVSS 3.1 7.5 HIGHEUVD CVSS 4.0 8.7 CVSS 4.0 · [email protected] · Secondary 8.7 HIGHCVSS 3.1 · [email protected] · Secondary 7.5 HIGHCVSS_V4 Publisher rating HIGHFixed by devalue 5.9.3KEV status unknown

Original advisory

cve-program · CVE-2026-123565

Published

Sveltejs devalue before 5.9.3 contains a resource exhaustion vulnerability where repeated primitive strings cause quadratic expansion in the uneval function. Attackers can supply a small crafted payload that is parsed and then passed to uneval, producing a very large serialized string that exhausts memory or CPU.

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euvd · EUVD-2026-119450

Published

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nvd · CVE-2026-123565

Published

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osv · GHSA-mcm9-63f2-9j32

Published

Under very constrained circumstances, data that was `parse`d and then passed to `uneval` could turn a small payload into a very large serialized string.

Read the publisher's advisory

Affected versions, risk and source history

Exploitation and risk

Source status

CISA KEV lists vulnerabilities known to be exploited. FIRST EPSS estimates the likelihood of exploitation in the next 30 days. An unavailable score does not mean zero risk.

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cve-program · CVE-2026-123565

Published

Devalue before 5.9.3 Quadratic Expansion Denial of Service via uneval

Source published: 8 Nov 2026 01:38:04 UTC
Source modified: 10 Nov 2026 17:58:28 UTC
Saved here: 10 Nov 2026 19:21:22 UTC
Source terms: CVE Program Terms of Use

Original source record · Cite this exact observation · Complete original publisher JSON

Source: cve-program · CVE Program Terms of Use. The publisher's wording is preserved. ChangeIntel groups the information and labels changes. The JSON record includes additional source fields.

CVSS 4.0 · 8.7 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

CVSS 3.1 · 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

euvd · EUVD-2026-119450

Published

Sveltejs devalue before 5.9.3 contains a resource exhaustion vulnerability where repeated primitive strings cause quadratic expansion in the uneval function. Attackers can supply a small crafted payload that is parsed and then passed to une…

Additional publisher context

EUVD source date text has no stated timezone and is retained without inventing a UTC instant. Related bulletin membership is not an alias, common cause or applicability claim. A missing vector with a zero score is treated as unrated. Complete vendor/product and underlying source evidence remains in the original JSON.

Original publisher date fields

datePublished: Nov 8, 2026, 1:38:04 AM

dateUpdated: Nov 10, 2026, 5:58:28 PM

Source published: Nov 8, 2026, 1:38:04 AM (timezone not stated)
Source modified: Nov 10, 2026, 5:58:28 PM (timezone not stated)
Saved here: 14 Nov 2026 11:58:31 UTC
Source terms: ENISA EUVD · source terms and attribution apply

Original source record · Cite this exact observation · Complete original publisher JSON

Source: euvd · ENISA EUVD · source terms and attribution apply. The publisher's wording is preserved. ChangeIntel groups the information and labels changes. The JSON record includes additional source fields.

EUVD CVSS 4.0 · 8.7 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

nvd · CVE-2026-123565

Published

Sveltejs devalue before 5.9.3 contains a resource exhaustion vulnerability where repeated primitive strings cause quadratic expansion in the uneval function. Attackers can supply a small crafted payload that is parsed and then passed to une…

Additional publisher context

NVD analysis and CPE criteria are source context, not proof that a package or your environment is affected. Complete affected data, logical configurations and SSVC are retained in the original JSON.

Source analysis status: Awaiting Analysis

Weakness classifications: CWE-400

Original publisher date fields

published: 2026-11-08T02:16:49.040

lastModified: 2026-11-12T20:28:31.817

Source published: 8 Nov 2026 02:16:49 UTC
Source modified: 12 Nov 2026 20:28:31 UTC
Saved here: 14 Nov 2026 12:57:57 UTC
Source terms: NIST NVD usage terms; underlying source attribution retained

Original source record · Cite this exact observation · Complete original publisher JSON

Source: nvd · NIST NVD usage terms; underlying source attribution retained. The publisher's wording is preserved. ChangeIntel groups the information and labels changes. The JSON record includes additional source fields.

CVSS 4.0 · [email protected] · Secondary · 8.7 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

CVSS 3.1 · [email protected] · Secondary · 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

osv · GHSA-mcm9-63f2-9j32

Published

devalue: Repeated primitive strings cause quadratic expansion in uneval

Under very constrained circumstances, data that was `parse`d and then passed to `uneval` could turn a small payload into a very large serialized string.

Source published: 1 Oct 2026 15:17:29 UTC
Source modified: 8 Nov 2026 10:56:13 UTC
Saved here: 8 Nov 2026 11:04:43 UTC
Source terms: GitHub Advisory Database · CC-BY-4.0

Original source record · Cite this exact observation · Complete original publisher JSON

Source: osv · GitHub Advisory Database · CC-BY-4.0. The publisher's wording is preserved. ChangeIntel groups the information and labels changes. The JSON record includes additional source fields.

CVSS_V4 · CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

Publisher rating · HIGH