Tornado before 6.6 does not validate the max_age argument of RequestHandler.set_cookie (also called by set_signed_cookie, set_secure_cookie, and clear_cookie), allowing injection of additional Set-Cookie attributes. When an application passes attacker-influenced input as max_age, an attacker can embed attributes such as Domain, Path, or Secure to widen the cookie's scope to parent paths or other subdomains.
{
"cna_assigner": "VulnCheck",
"cwe_ids": [
"CWE-74"
],
"osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/123xxx/CVE-2026-123535.json"
}{
"extracted_events": [
{
"range": [
{
"introduced": "0"
},
{
"fixed": "6.6"
}
],
"source": "AFFECTED_FIELD",
"strategy": "StandardRange"
},
{
"range": [
{
"introduced": "0"
},
{
"fixed": "6.6"
}
],
"source": "DESCRIPTION"
}
]
}