{"id":"CVE-2026-123564","aliases":["EUVD-2026-119449","GHSA-97c7-3pc7-pw7r"],"status":"published","title":"Sveltejs devalue before 5.9.3 Memory Exhaustion via uneval Sparse Arrays","description":"Sveltejs devalue from 1.0.0 before 5.9.3 contains a memory exhaustion flaw in uneval, whose generated code for sparse arrays allocates memory proportional to the array's declared length when evaluated. Attackers who can influence a very large sparse array serialized by an application can exhaust memory in the browser or runtime evaluating the output.","severity":{"version":"4.0","score":8.7,"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","level":"high","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-12","score":0.00343,"percentile":0.28273,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":false},"cwes":["CWE-770"],"published":"2026-11-08T01:38:03Z","modified":"2026-11-08T10:45:32Z","products":[{"vendor":"sveltejs","product":"devalue"}],"references":[{"url":"https://github.com/sveltejs/devalue/security/advisories/GHSA-wf3x-273g-mvxv","tags":["vendor-advisory","advisory"]},{"url":"https://www.vulncheck.com/advisories/sveltejs-devalue-before-5.9.3-memory-exhaustion-via-uneval-sparse-arrays","tags":["third-party-advisory","advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-123564","tags":["advisory"]},{"url":"https://github.com/advisories/GHSA-97c7-3pc7-pw7r"},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/123xxx/CVE-2026-123564.json","tags":["advisory"]}],"sources":{"cve":[{"id":"CVE-2026-123564","title":"Sveltejs devalue before 5.9.3 Memory Exhaustion via uneval Sparse Arrays","description":"Sveltejs devalue from 1.0.0 before 5.9.3 contains a memory exhaustion flaw in uneval, whose generated code for sparse arrays allocates memory proportional to the array's declared length when evaluated. Attackers who can influence a very large sparse array serialized by an application can exhaust memory in the browser or runtime evaluating the output.","status":"published","published":"2026-11-08T01:38:03.802Z","modified":"2026-11-12T13:02:42.004Z","cvss":[{"version":"4.0","score":8.7,"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","level":"high","assessor":"cna"},{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high","assessor":"cna"}],"cwes":["CWE-770"],"updated_at":"2026-11-08T02:36:49.037074Z"}],"euvd":[{"id":"EUVD-2026-119449","description":"Sveltejs devalue from 1.0.0 before 5.9.3 contains a memory exhaustion flaw in uneval, whose generated code for sparse arrays allocates memory proportional to the array's declared length when evaluated. Attackers who can influence a very large sparse array serialized by an application can exhaust memory in the browser or runtime evaluating the output.","status":"published","published":"2026-11-08T01:38:03Z","modified":"2026-11-12T13:02:42Z","cvss":[{"version":"4.0","score":8.7,"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","level":"high"}],"updated_at":"2026-11-08T06:12:04.782489Z"}],"ghsa":[{"id":"GHSA-97c7-3pc7-pw7r","title":"Sveltejs devalue from 1.0.0 before 5.9.3 contains a memory exhaustion flaw in uneval, whose...","description":"Sveltejs devalue from 1.0.0 before 5.9.3 contains a memory exhaustion flaw in uneval, whose generated code for sparse arrays allocates memory proportional to the array's declared length when evaluated. Attackers who can influence a very large sparse array serialized by an application can exhaust memory in the browser or runtime evaluating the output.","status":"published","published":"2026-11-08T03:30:33Z","modified":"2026-11-08T03:30:34Z","cvss":[{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high"},{"version":"4.0","score":8.7,"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/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","level":"high"}],"cwes":["CWE-770"],"updated_at":"2026-11-08T03:41:53.166172Z"}],"nvd":[{"id":"CVE-2026-123564","description":"Sveltejs devalue from 1.0.0 before 5.9.3 contains a memory exhaustion flaw in uneval, whose generated code for sparse arrays allocates memory proportional to the array's declared length when evaluated. Attackers who can influence a very large sparse array serialized by an application can exhaust memory in the browser or runtime evaluating the output.","status":"published","published":"2026-11-08T02:16:48.877Z","modified":"2026-11-12T13:17:14.363Z","cvss":[{"version":"4.0","score":8.7,"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/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","level":"high","assessor":"secondary"},{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high","assessor":"secondary"}],"cwes":["CWE-770"],"updated_at":"2026-11-12T15:31:32.275584Z"}],"osv":[{"id":"CVE-2026-123564","title":"Sveltejs devalue before 5.9.3 Memory Exhaustion via uneval Sparse Arrays","description":"Sveltejs devalue from 1.0.0 before 5.9.3 contains a memory exhaustion flaw in uneval, whose generated code for sparse arrays allocates memory proportional to the array's declared length when evaluated. Attackers who can influence a very large sparse array serialized by an application can exhaust memory in the browser or runtime evaluating the output.","status":"published","published":"2026-11-08T01:38:03.802Z","modified":"2026-11-09T02:47:17.634986327Z","cvss":[{"version":"4.0","score":8.7,"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","level":"high"}],"cwes":["CWE-770"],"updated_at":"2026-11-08T11:04:05.022583Z"}]}}