CVE-2024-49768
Waitress has request processing race condition in HTTP pipelining with invalid first request
Description
Waitress is a Web Server Gateway Interface server for Python 2 and 3. A remote client may send a request that is exactly recv_bytes (defaults to 8192) long, followed by a secondary request using HTTP pipelining. When request lookahead is disabled (default) we won't read any more requests, and when the first request fails due to a parsing error, we simply close the connection. However when request lookahead is enabled, it is possible to process and receive the first request, start sending the error message back to the client while we read the next request and queue it. This will allow the secondary request to be serviced by the worker thread while the connection should be closed. Waitress 3.0.1 fixes the race condition. As a workaround, disable channel_request_lookahead, this is set to 0 by default disabling this feature.
How to fix CVE-2024-49768
To remediate CVE-2024-49768, upgrade the affected package to a fixed version below.
- —upgrade to 2.1.2-2+deb12u1 or later
- —upgrade to 3.0.1 or later
- —upgrade to e4359018537af376cf24bd13616d861e2fb76f65 or later
Is CVE-2024-49768 being exploited?
Low — EPSS is 0.6%, meaning exploitation activity has not been observed at scale.
Affected packages (3)
- from 0, < 2.1.2-2+deb12u1
- >= 2.0.0, < 3.0.1
- from 0, < e4359018537af376cf24bd13616d861e2fb76f65 | >= 2.0.0, < 3.0.1
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 4.0 | — | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N |
| osv | CVSS 3.1 | CRITICAL9.1 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N |