CVE-2026-91991Medium· 5.4▾ TwilightPoC availableTornado before 6.5.8 contains an incomplete fix for cookie attribute injection that allows attackers to inject arbitrary cookie attributes by passing capitalized or legacy keyword arguments to set_cookie. Attackers can embed semicolon-de…
▾ Twilight zone — High severity, or a signal on a lesser flaw
impact 29.7 · likelihood 0 · exploitation 12
A public proof-of-concept already exists for this vulnerability — see Exploit availability below.
Stakeholder-Specific Vulnerability Categorization from CISA's ADP record at CVE.org: whether exploitation is observed, whether an attack can be automated, and how much of the system is at stake.
Exploit-prediction probability, daily snapshots since Sep 19.
Disclosure to exploitation, from the record and what we observed since indexing it.
Disclosed via NVD
0.2%
Exploit / PoC code exists
0.2% → 0.3%
Last analysed / modified upstream
Tornado before 6.5.8 contains an incomplete fix for cookie attribute injection that allows attackers to inject arbitrary cookie attributes by passing capitalized or legacy keyword arguments to set_cookie. Attackers can embed semicolon-delimited data in capitalized parameters like Domain, Path, or SameSite to bypass validation and modify cookie security attributes.
Refer to the linked advisories for vendor-supplied fixes and affected version ranges.
Affected packages:
tornado >= 6.5.5, < 6.5.8Patched in:
tornado 6.5.8Source: https://osv.dev/vulnerability/GHSA-wwv5-g3v4-889x
Field changes observed since this record was first indexed.
Connected by shared product, vendor, weakness, or advisory.
CVE-2026-91990High· 7.5Tornado before 6.5.8 contains a memory amplification vulnerability in parse_multipart_form_data that splits multipart data before validating the max_parts limit
CVE-2026-82397High· 7.5Tornado is a Python web framework and asynchronous networking library
CVE-2024-58384Medium· 5.4Tornado before 6.4.1 contains a CRLF injection vulnerability in CurlAsyncHTTPClient that fails to reject carriage return and line feed characters in request headers
CVE-2026-103262High· 7.5Tornado versions before 6.5.9 contain an unbounded memory accumulation vulnerability in CurlAsyncHTTPClient that allows remote attackers to cause denial of service by sending a compressed response
CVE-2026-103263Medium· 5.9Tornado before 6.5.9 contains a path traversal vulnerability in StaticFileHandler that follows symbolic links inside the static root without confirming the resolved target stays within it
CVE-2024-14029High· 7.5Tornado before 6.4.1 ignores duplicate Transfer-Encoding: chunked headers, treating requests as having no message body and parsing the chunked body as a subsequent request