CVE-2026-49855
Tornado is a Python web framework and asynchronous networking library. Prior to 6.5.6, Tornado gzip decompression routines processed limited-size chunks but did not enforce an overall limit on accumulated decompressed chunks, allowing a malicious server accessed by SimpleAsyncHTTPClient or an HTTPServer configured with decompress_request=True to consume effectively unlimited memory. This issue is fixed in version 6.5.6.
- CVSS 3.1
- 7.5
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - EPSS
- 0.6% chance of exploitation in the next 30 days; higher than 47% of CVEs (scores of 2026-10-25)
- CWE
- CWE-409
- Published
- Modified
- Record from
- the NVD, synced
Packages (OSV)
| Advisory | Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|---|
| GHSA-mgf9-4vpg-hj56 | PyPI | tornado | <6.5.6 | 6.5.6 |
| PYSEC-2026-3389 | PyPI | tornado | <6.5.6 | 6.5.6 |