SiYuan 3.7.0 before 3.8.10 on Windows contains a path traversal vulnerability in kernel/util/webfetch.go that allows attackers to write files outside the import directory via backslash-encoded filenames. Attackers controlling a URL fetched by the MCP web_fetch or http_request tools can use %5C-encoded ..\ sequences to write chosen response bytes to directories above temp/import that are writable by the SiYuan user.
{
"cna_assigner": "VulnCheck",
"cwe_ids": [
"CWE-22"
],
"osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/126xxx/CVE-2026-126776.json",
"unresolved_ranges": [
{
"extracted_events": [
{
"range": [
{
"introduced": "3.7.0"
},
{
"fixed": "3.8.10"
}
],
"source": "AFFECTED_FIELD",
"strategy": "StandardRange"
}
]
},
{
"extracted_events": [
{
"range": [
{
"introduced": "3.7.0"
},
{
"fixed": "3.8.10"
}
],
"source": "CPE_FIELD",
"strategy": "CPEApplicability"
}
]
},
{
"extracted_events": [
{
"range": [
{
"introduced": "3.7.0"
},
{
"fixed": "3.8.10"
}
],
"source": "DESCRIPTION"
}
]
}
]
}{
"extracted_events": [
{
"range": [
{
"fixed": "94d6a42a0362c0a6938a29ab84addb1fe0aca21c"
}
],
"source": "REFERENCES_COMMIT"
},
{
"original_tag": "v3.8.10",
"range": [
{
"fixed": "be17ed1e0510bb6371cb8a162e16898a697fa118"
}
],
"source": "REFERENCES_TAG"
}
]
}