CVE-2026-123565
📛 CVE Title
Devalue before 5.9.3 Quadratic Expansion Denial of Service via uneval
Description
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.
Overview
- State
- PUBLISHED
- Assigner (CNA)
- VulnCheck
- CVSS severity
- HIGH
- CVSS score
- 8.7 / 10
- CVSS vector
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- Effective score
- 8.7 / 10 HIGH source: CNA overview
- CWE(s)
-
CWE-400 - Reserved
- 2026-11-06
- Published
- 2026-11-08 01:38 UTC
- Last updated
- 2026-11-08 01:38 UTC
- Source
- https://raw.githubusercontent.com/CVEProject/cvelistV5/main/cves/2026/123xxx/CVE-2026-123565.json
- Linked Threat
- CVE-2026-123565 — Devalue before 5.9.3 Quadratic Expansion Denial of Service via uneval
European Union Vulnerability Database ENISA EUVD
ENISA's official EU repository for curated vulnerability intelligence. Carries a separate identifier (EUVD-YYYY-NNNN) and frequently exposes an earlier-published description + CVSS than NVD does.
- EUVD ID
-
EUVD-2026-119450
EUVD enrichment is queued; refresh the page in a few seconds.
Affected products (1)
| Vendor | Product | Versions | Platforms |
|---|---|---|---|
| sveltejs | devalue |
0 (affected),
5.9.3 (unaffected)
|
— |
Vendor references (2)
References embedded in the original CVE record by the assigning CNA.
- GitHub Security Advisory (GHSA-mcm9-63f2-9j32) vendor-advisory
- VulnCheck Advisory: Devalue before 5.9.3 Quadratic Expansion Denial of Service via uneval third-party-advisory
Web references (0)
DuckDuckGo results ranked by threat-intel / vendor advisory domains. Generated by the 🔎 Find references (web) button above — same flow as the Remediations search.
No web references attached yet.
Remediations (10)
Remediations are stored against the linked Threat row; the list below is deduplicated across both pages.
-
web:cvedatabase.com
Search and analyze CVE vulnerabilities with instant access to CVSS scores, affected products, and remediation guidance.
2026-11-08 10:24 UTC -
web:cybersecuritynews.com
The U.S. Cybersecurity and Infrastructure Security Agency (CISA) has issued Binding Operational Directive (BOD) 26-04, titled "Prioritizing Security Updates Based on Risk," compelling all Federal Civilian Executive Branch (FCEB) agencies to remediate the most dangerous known exploited vulnerabilities within just three calendar days.
2026-11-08 10:24 UTC -
web:cyberupdates365.com
Track critical CVE vulnerabilities 2026 with verified enterprise patch guides. Fix zero-days across VMware, WordPress, Windows, and cloud infrastructure.
2026-11-08 10:24 UTC -
web:sec.cloudapps.cisco.com
As part of Cisco's ongoing commitment to proactive security and product quality, engineering teams conducted a comprehensive internal security review. This review resulted in software hardening releases that address multiple internally discovered vulnerabilities. These vulnerabilities were found during internal testing and are not known to be actively exploited. To assist customers in patching ...
2026-11-08 10:24 UTC -
web:senserva.com
Every Microsoft security patch (KB) and the CVEs it fixes, with severity, CVSS, and CISA KEV status. Cross-linked to the CVE reference.
2026-11-08 10:24 UTC -
web:support.esri.com
This patch deals specifically with the issues listed below under Issues Addressed with this Patch . As part of the patch installation, the Portal for ArcGIS service is stopped and restarted. The restart may take several minutes depending on the number of items on the enterprise deployment. As a best practice, clear the browser cache and re-launch the browser after installing the patch . This ...
2026-11-08 10:24 UTC -
web:www.aikido.dev
CVE remediation is fixing known flaws in the software you run. Why upgrading often fails, what remediation actually involves, and how backporting fixes it.
2026-11-08 10:24 UTC -
web:www.microsoft.com
The built-in PHP runtimes on App Service for Windows are end of life, so move those apps to App Service on Linux or bring your own supported PHP runtime. If you can't patch immediately: Apply the PHP project's interim mitigations and the Azure WAF protections. Note: This reduces exposure but doesn't fix the underlying vulnerabilities.
2026-11-08 10:24 UTC -
web:www.openhands.dev
Compare 8 automated vulnerability remediation tools for 2026 on fixes, prioritization, integrations, and deployment control.
2026-11-08 10:24 UTC -
web:www.oracle.com
Prior Critical Patch Update and Critical Security Patch Update advisories should be reviewed for information regarding earlier published security patches. Refer to Critical Patch Updates, Critical Security Patch Updates, Security Alerts and Bulletins for information about Oracle Security advisories.
2026-11-08 10:24 UTC
AI Forensic Analysis
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Raw JSON
The full cvelistV5 record. Download as CVE-2026-123565.json.
{
"containers": {
"cna": {
"affected": [
{
"defaultStatus": "unaffected",
"packageURL": "pkg:npm/devalue",
"product": "devalue",
"vendor": "sveltejs",
"versions": [
{
"lessThan": "5.9.3",
"status": "affected",
"version": "0",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "5.9.3",
"versionType": "semver"
}
]
}
],
"cpeApplicability": [
{
"nodes": [
{
"cpeMatch": [
{
"criteria": "cpe:2.3:a:svelte:devalue:*:*:*:*:*:*:*:*",
"versionEndExcluding": "5.9.3",
"vulnerable": true
}
],
"negate": false,
"operator": "OR"
}
]
}
],
"credits": [
{
"lang": "en",
"type": "remediation developer",
"value": "elliott-with-the-longest-name-on-github"
}
],
"datePublic": "2026-09-18T00:00:00.000Z",
"descriptions": [
{
"lang": "en",
"value": "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."
}
],
"metrics": [
{
"cvssV4_0": {
"Automatable": "NOT_DEFINED",
"Recovery": "NOT_DEFINED",
"Safety": "NOT_DEFINED",
"attackComplexity": "LOW",
"attackRequirements": "NONE",
"attackVector": "NETWORK",
"baseScore": 8.7,
"baseSeverity": "HIGH",
"exploitMaturity": "NOT_DEFINED",
"privilegesRequired": "NONE",
"providerUrgency": "NOT_DEFINED",
"subAvailabilityImpact": "NONE",
"subConfidentialityImpact": "NONE",
"subIntegrityImpact": "NONE",
"userInteraction": "NONE",
"valueDensity": "NOT_DEFINED",
"vectorString": "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",
"version": "4.0",
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"vulnerabilityResponseEffort": "NOT_DEFINED"
},
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{
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"baseScore": 7.5,
"baseSeverity": "HIGH",
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"integrityImpact": "NONE",
"privilegesRequired": "NONE",
"scope": "UNCHANGED",
"userInteraction": "NONE",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
"version": "3.1"
},
"format": "CVSS"
}
],
"problemTypes": [
{
"descriptions": [
{
"cweId": "CWE-400",
"description": "Uncontrolled Resource Consumption",
"lang": "en",
"type": "CWE"
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}
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"providerMetadata": {
"dateUpdated": "2026-11-08T01:38:04.469Z",
"orgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10",
"shortName": "VulnCheck"
},
"references": [
{
"name": "GitHub Security Advisory (GHSA-mcm9-63f2-9j32)",
"tags": [
"vendor-advisory"
],
"url": "https://github.com/sveltejs/devalue/security/advisories/GHSA-mcm9-63f2-9j32"
},
{
"name": "VulnCheck Advisory: Devalue before 5.9.3 Quadratic Expansion Denial of Service via uneval",
"tags": [
"third-party-advisory"
],
"url": "https://www.vulncheck.com/advisories/devalue-before-5.9.3-quadratic-expansion-denial-of-service-via-uneval"
}
],
"title": "Devalue before 5.9.3 Quadratic Expansion Denial of Service via uneval",
"x_generator": {
"engine": "vulncheck-endgame"
}
}
},
"cveMetadata": {
"assignerOrgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10",
"assignerShortName": "VulnCheck",
"cveId": "CVE-2026-123565",
"datePublished": "2026-11-08T01:38:04.469Z",
"dateReserved": "2026-11-06T00:53:14.312Z",
"dateUpdated": "2026-11-08T01:38:04.469Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}