What is CVE-2024-49768?

CVE-2024-49768 is a critical-severity vulnerability in Agendaless Waitress, classified under Time-of-check Time-of-use (TOCTOU) Race Condition. CVSS score: 9.1/10. Published 2024-10-29.

How severe is CVE-2024-49768?

Critical severity. CVSS v3 base score is 9.1 out of 10.

Is CVE-2024-49768 known to be exploited?

6 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.

Vulnerability in Agendaless Waitress

CVE-2024-49768

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.

Vulnerability class: TOCTOU (Time-of-Check to Time-of-Use)

Published 2024-10-29 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 9.1 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N.

EPSS exploit prediction

EPSS: 0.005 (39.4th percentile), scored 2026-09-30.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 39th percentile — 39.4% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.005 · newest: 0.005 · change: 0.000

Affected products

Agendaless Waitress
Pylons Waitress — versions >= 2.0.0, < 3.0.1

Weakness classification (CWE)

Public proof-of-concept exploits

References

github.com/Pylons/waitress/security/advisories/GHSA-9298-4cf8-g4wj (Vendor Advisory)
github.com/Pylons/waitress/commit/e4359018537af376cf24bd13616d861e2fb76f65 (Patch)

Frequently asked questions

What is CVE-2024-49768?: CVE-2024-49768 is a critical-severity vulnerability in Agendaless Waitress, classified under Time-of-check Time-of-use (TOCTOU) Race Condition. CVSS score: 9.1/10. Published 2024-10-29.
How severe is CVE-2024-49768?: Critical severity. CVSS v3 base score is 9.1 out of 10.
Is CVE-2024-49768 known to be exploited?: 6 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.