GHSA-JRFJ-FHJ2-JJVM
Vulnerability from github – Published: 2026-10-07 20:23 – Updated: 2026-10-07 20:23Opening 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.
spinCount (crypt.go:98) is a plain int filled by a bare xml.Unmarshal of the file's own EncryptionInfo stream. Nothing bounds it.
A 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.
v2.5.0 spinCount=10000000 5.307s
v2.9.1 spinCount=10000000 5.444s
v2.11.0 spinCount=10000000 7.529s
v2.11.0 spinCount=100000000 58.654s
The loop arrived with crypt.go in v2.3.1 and is unchanged through v2.11.0.
Excel and LibreOffice write spinCount 100000, which costs 61ms here, so a ceiling well above the legitimate value would cost real files nothing.
This is availability only, and it is not a vulnerability for a program that only opens files its own operator produced.
{
"affected": [
{
"package": {
"ecosystem": "Go",
"name": "github.com/xuri/excelize/v2"
},
"ranges": [
{
"events": [
{
"introduced": "2.3.1"
},
{
"fixed": "2.11.1-0.20260906004932-2badfcd5841d"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [
"CVE-2026-107219"
],
"database_specific": {
"cwe_ids": [
"CWE-400"
],
"github_reviewed": true,
"github_reviewed_at": "2026-10-07T20:23:22Z",
"nvd_published_at": null,
"severity": "HIGH"
},
"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\u0027s 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.",
"id": "GHSA-jrfj-fhj2-jjvm",
"modified": "2026-10-07T20:23:22Z",
"published": "2026-10-07T20:23:22Z",
"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"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
"type": "CVSS_V3"
}
],
"summary": "Excelize: Unbounded spinCount in agile decryption burns CPU during OpenFile"
}
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