How severe is CVE-2024-49768?

CVE-2024-49768 has a CVSS score of 9.1/10, rated CRITICAL. Immediate patching is strongly recommended.

Which packages are affected by CVE-2024-49768?

CVE-2024-49768 affects the following packages: waitress (PyPI). Ecosystems affected: PyPI.

How do I fix CVE-2024-49768?

Update waitress to 3.0.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2024-49768 is resolved across your whole dependency graph.

How do I detect CVE-2024-49768 in my PyPI dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for waitress, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2024-49768 if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Is CVE-2024-49768 actively exploited in the wild?

No public exploit code has been indexed for CVE-2024-49768 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2024-49768?

CVE-2024-49768 has an EPSS (Exploit Prediction Scoring System) score of 0.5%, placing it in the 42th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2024-49768?

CVE-2024-49768 is classified as CWE-367 (CWE-367), CWE-444 (CWE-444). These weakness types describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2024-49768 published, and has it been updated?

CVE-2024-49768 was published on October 29, 2024 and was last updated on October 28, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐍

🐍 PyPI

Not in CISA KEV

CRITICAL severity

CVE-2024-49768 — waitress

CRITICALFix: Pylons/waitress@e435901

CVE-2024-49768 is a critical-severity (CVSS 9.1) CWE-367 vulnerability in waitress. A fix is available for waitress — see the affected versions and patch details below.

Waitress has request processing race condition in HTTP pipelining with invalid first request

Also known asGHSA-9298-4cf8-g4wjPYSEC-2024-210

Published

Oct 29, 2024

Updated

Oct 28, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Nov 4, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
A successful exploit gives an attacker total control of the affected component, not partial access.
CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for CVE-2024-49768.

EPSS Exploitation Probability

via FIRST.org ↗

0.5%probability of exploitation in next 30 days

Lower Risk-0.09%

Lower risk than most CVEs42th percentile — riskier than 42% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

1 pkg affected

🐍waitress

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.

Description

Impact

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.

Patches

Waitress 3.0.1 fixes the race condition.

Workarounds

Disable channel_request_lookahead, this is set to 0 by default disabling this feature. For this vulnerability this value is required to be changed from the default.

For more information

If you have any questions or comments about this advisory:

Open an issue in https://github.com/Pylons/waitress/issues (if not sensitive or security related)
email the Pylons Security mailing list: [email protected] (if security related)

Thanks

m4yfly and urn1ce From TianGong Team of Legendsec at Qi'anxin Group.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🐍PyPI	`waitress`	≥ 2.0.0&&< 3.0.1	3.0.1`pip install --upgrade 'waitress==3.0.1'`

Affected Products

1 product · 1 configurations

Application

waitressagendaless

≥ 2.0.0 && < 3.0.1

range

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for waitress, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update waitress to 3.0.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2024-49768 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Fixing This On Your OS

If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.

Red HatImportant

Workaround published by Red Hat

Disable `channel_request_lookahead`. This feature is disabled (set to 0) by default.

Source: Red Hat security advisory for CVE-2024-49768 (CC BY 4.0)

Product	Fixed in	Advisory
Ironic content for Red Hat OpenShift Container Platform 4.12	`python-waitress-0:3.0.1-1.el9`	RHSA-2024:10535
Ironic content for Red Hat OpenShift Container Platform 4.13	`python-waitress-0:3.0.1-1.el9`	RHSA-2024:10815
Red Hat OpenShift Container Platform 4.14	`python-waitress-0:3.0.1-1.el9`	RHSA-2024:9623
Red Hat OpenShift Container Platform 4.15	`python-waitress-0:3.0.1-1.el9`	RHSA-2024:10145
Red Hat OpenShift Container Platform 4.16	`python-waitress-0:3.0.1-1.el9`	RHSA-2024:9618
Red Hat OpenShift Container Platform 4.17	`python-waitress-0:3.0.1-1.el9`	RHSA-2024:9613
Red Hat OpenStack Platform 16.2	`python-waitress-0:2.0.0-4.el8ost`	RHSA-2025:0201
Red Hat OpenStack Platform 17.1 for RHEL 8	`python-waitress-0:2.0.0-4.el8ost`	RHSA-2025:1192

Frequently Asked Questions

### Impact 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