{"id":"GHSA-jrfj-fhj2-jjvm","summary":"Excelize: Unbounded spinCount in agile decryption burns CPU during OpenFile","details":"Opening a file whose first eight bytes are the OLE magic number sends excelize down the decryption path whether or not the caller set a password, or supports encrypted workbooks at all. `openReaderAt` (excelize.go:198-215) branches on the header alone, and `agileDecrypt` calls `convertPasswdToKey` before the verifier hash is checked, so the key-derivation loop runs `spinCount` times regardless.\n\n`spinCount` (crypt.go:98) is a plain `int` filled by a bare `xml.Unmarshal` of the file's own EncryptionInfo stream. Nothing bounds it.\n\nA 3072-byte file with spinCount 100000000 makes `OpenFile` take 58.65s on v2.11.0 with default options, then return `zip: not a valid zip file`. It is linear at about 0.6 microseconds per iteration and the attacker picks the number, so 1e9 is roughly ten minutes. Nothing on the path takes a `context.Context`, so the caller cannot cancel it; in an HTTP handler the write timeout returns a response while the goroutine keeps spinning. Memory stays flat at 24 MB, so nothing reclaims it either.\n\n```\nv2.5.0   spinCount=10000000   5.307s\nv2.9.1   spinCount=10000000   5.444s\nv2.11.0  spinCount=10000000   7.529s\nv2.11.0  spinCount=100000000  58.654s\n```\n\nThe loop arrived with `crypt.go` in v2.3.1 and is unchanged through v2.11.0.\n\nExcel and LibreOffice write spinCount 100000, which costs 61ms here, so a ceiling well above the legitimate value would cost real files nothing. \n\nThis is availability only, and it is not a vulnerability for a program that only opens files its own operator produced.","aliases":["CVE-2026-107219"],"modified":"2026-10-07T20:30:05.832809888Z","published":"2026-10-07T20:23:22Z","database_specific":{"severity":"HIGH","github_reviewed":true,"github_reviewed_at":"2026-10-07T20:23:22Z","nvd_published_at":null,"cwe_ids":["CWE-400"]},"references":[{"type":"WEB","url":"https://github.com/qax-os/excelize/security/advisories/GHSA-jrfj-fhj2-jjvm"},{"type":"WEB","url":"https://github.com/qax-os/excelize/pull/2389"},{"type":"WEB","url":"https://github.com/qax-os/excelize/commit/2badfcd5841d0d88b0ffea119f5a2f3c53b4910b"},{"type":"PACKAGE","url":"https://github.com/qax-os/excelize"}],"affected":[{"package":{"name":"github.com/xuri/excelize/v2","ecosystem":"Go","purl":"pkg:golang/github.com/xuri/excelize/v2"},"ranges":[{"type":"SEMVER","events":[{"introduced":"2.3.1"},{"fixed":"2.11.1-0.20260906004932-2badfcd5841d"}]}],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/10/GHSA-jrfj-fhj2-jjvm/GHSA-jrfj-fhj2-jjvm.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"}]}