SB2026042837 - Ubuntu update for python-tornado
Published: April 28, 2026
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 2 secuirty vulnerabilities.
1) Resource exhaustion (CVE-ID: CVE-2026-31958)
The vulnerability allows a remote attacker to cause a denial of service.
The vulnerability exists due to uncontrolled resource consumption in multipart/form-data parsing on the main thread when processing very large multipart request bodies with many parts. A remote attacker can send a specially crafted multipart/form-data request to cause a denial of service.
The number of multipart parts is limited only by the max_body_size setting.
2) Improper Neutralization of Special Elements in Output Used by a Downstream Component (CVE-ID: CVE-2026-35536)
The vulnerability allows a remote attacker to inject attacker-controlled cookie attributes.
The vulnerability exists due to improper neutralization of special elements in output used by a downstream component in RequestHandler.set_cookie when processing the domain, path, and samesite arguments. A remote attacker can supply input containing semicolons to inject attacker-controlled cookie attributes.
User interaction is required for exploitation.
Remediation
Install update from vendor's website.