Waitress is a Web Server Gateway Interface server for Python 2 and 3. When using Waitress versions 2.1.0 and prior behind a proxy that does not properly validate the incoming HTTP request matches the RFC7230 standard, Waitress and the frontend proxy may disagree on where one request starts and where it ends. This would allow requests to be smuggled via the front-end proxy to waitress and later behavior. There are two classes of vulnerability that may lead to request smuggling that are addressed by this advisory: The use of Python's int() to parse strings into integers, leading to +10 to be parsed as 10, or 0x01 to be parsed as 1, where as the standard specifies that the string should contain only digits or hex digits; and Waitress does not support chunk extensions, however it was discarding them without validating that they did not contain illegal characters. This vulnerability has been patched in Waitress 2.1.1. A workaround is available. When deploying a proxy in front of waitress, turning on any and all functionality to make sure that the request matches the RFC7230 standard. Certain proxy servers may not have this functionality though and users are encouraged to upgrade to the latest version of waitress instead.
CVE-2022-24761
This high-severity CVE scores 7.5 under NVD CVSS v3. EPSS exploit probability: 0.3%, top 42% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).
- High severity, but no confirmed exploitation yet
A fix is available — apply it.
- CVSS v3
- 7.5
- EG Score
- 7.5(medium)
- EPSS
- 75.0%
- KEV
- Not listed
Published
March 17, 2022
Last Modified
November 21, 2024
References (10)
- security-advisories@githubhttps://github.com/Pylons/waitress/commit/9e0b8c801e4d505c2ffc91b891af4ba48af715e0
- security-advisories@githubhttps://github.com/Pylons/waitress/releases/tag/v2.1.1
- security-advisories@githubhttps://github.com/Pylons/waitress/security/advisories/GHSA-4f7p-27jc-3c36
- security-advisories@githubhttps://lists.debian.org/debian-lts-announce/2022/05/msg00011.html
- security-advisories@githubhttps://www.debian.org/security/2022/dsa-5138
- af854a3a-2127-422b-91ae-364da2661108https://github.com/Pylons/waitress/commit/9e0b8c801e4d505c2ffc91b891af4ba48af715e0
- af854a3a-2127-422b-91ae-364da2661108https://github.com/Pylons/waitress/releases/tag/v2.1.1
- af854a3a-2127-422b-91ae-364da2661108https://github.com/Pylons/waitress/security/advisories/GHSA-4f7p-27jc-3c36
- af854a3a-2127-422b-91ae-364da2661108https://lists.debian.org/debian-lts-announce/2022/05/msg00011.html
- af854a3a-2127-422b-91ae-364da2661108https://www.debian.org/security/2022/dsa-5138
Patch Availability(3)
| Vendor / Ecosystem | Fixed in / Patch | Released | Source |
|---|---|---|---|
| ubuntu | python3-waitress (1.4.4-1.1ubuntu0.1) @ impish | 2026-05-26 | ubuntu |
| redhat | python-waitress-0:1.4.4-2.el7ost | 2022-04-07 | redhat |
| redhat | python-waitress-0:2.0.0-1.el8ost | 2022-04-06 | redhat |
Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.
Affected Packages
(1 across 1 ecosystem)
PyPI(1)
| Package | Vulnerable range | Fixed in | Dependents |
|---|---|---|---|
| waitress | 0.1 ... 2.1.0b0 (47 versions) | 2.1.1 | — |
Weakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
All Vendor Advisories
(5)
Every vendor that published an advisory referencing this CVE — pulled from our cve_vendor_advisories aggregation. Click any row for the vendor's original advisory page.
- Microsoft MSRCCVE-2022-247612025-03-14
HTTP Request Smuggling in waitress
- Red HatRHSA-2022:1253IMPORTANT2022-03-17
RHSA-2022:1253 — Important
- Red HatRHSA-2022:1254IMPORTANT2022-03-17
RHSA-2022:1254 — Important
- Red HatRHSA-2022:1264IMPORTANT2022-03-17
RHSA-2022:1264 — Important
- UbuntuUSN-5364-1MEDIUM
Waitress vulnerability
Data Freshness Timeline
(refreshed 8× in last 7d / 43× in last 30d)
Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.
- 2026-07-12 05:44 UTCEPSS rescore
- 2026-07-11 08:25 UTCEPSS rescore
- 2026-07-09 19:07 UTCEPSS rescore
- 2026-07-08 15:12 UTCEPSS rescore
- 2026-07-07 13:44 UTCEPSS rescore
- 2026-07-06 16:25 UTCEPSS rescore
- 2026-07-06 16:25 UTCEPSS rescore
- 2026-07-06 02:21 UTCEPSS rescore
- 2026-07-05 02:28 UTCEPSS rescore
- 2026-07-04 06:29 UTCEPSS rescore
- 2026-07-04 06:29 UTCEPSS rescore
- 2026-07-01 15:04 UTCEPSS rescore
- 2026-06-30 23:20 UTCEPSS rescore
- 2026-06-30 23:20 UTCEPSS rescore
- 2026-06-29 17:53 UTCOSV refresh
- 2026-06-28 14:06 UTCEPSS rescore
- 2026-06-28 04:54 UTCEPSS rescore
- 2026-06-28 04:54 UTCEPSS rescore
- 2026-06-27 03:07 UTCEPSS rescore
- 2026-06-25 13:48 UTCEPSS rescore
- 2026-06-24 14:03 UTCEPSS rescore
- 2026-06-24 14:03 UTCEPSS rescore
- 2026-06-23 21:31 UTCEPSS rescore
- 2026-06-23 21:31 UTCEPSS rescore
- 2026-06-22 14:24 UTCEPSS rescore
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- 2026-06-21 14:55 UTCEPSS rescore
- 2026-06-21 14:55 UTCEPSS rescore
- 2026-06-21 01:58 UTCEPSS rescore
- 2026-06-21 01:58 UTCEPSS rescore
- 2026-06-19 19:24 UTCEPSS rescore
- 2026-06-19 19:24 UTCEPSS rescore
- 2026-06-18 17:51 UTCEPSS rescore
- 2026-06-18 17:51 UTCEPSS rescore
- 2026-06-17 17:51 UTCEPSS rescore
- 2026-06-17 17:51 UTCEPSS rescore
- 2026-06-16 17:51 UTCEPSS rescore
- 2026-06-15 17:46 UTCEPSS rescore
- 2026-06-14 23:15 UTCEPSS rescore
- 2026-06-14 23:15 UTCEPSS rescore
- 2026-06-13 22:58 UTCEPSS rescore
- 2026-06-13 22:58 UTCEPSS rescore
- 2026-06-12 23:10 UTCEPSS rescore
- 2026-06-12 23:10 UTCEPSS rescore
- 2026-06-12 06:36 UTCOSV refresh
- 2026-06-11 13:58 UTCEPSS rescore
- 2026-06-11 13:58 UTCEPSS rescore
- 2026-06-10 22:16 UTCEPSS rescore
- 2026-06-10 13:20 UTCEPSS rescore
- 2026-06-08 14:15 UTCEPSS rescore
- 2026-06-08 14:15 UTCEPSS rescore
- 2026-06-07 15:23 UTCEPSS rescore
- 2026-06-07 15:23 UTCEPSS rescore
- 2026-06-06 13:46 UTCEPSS rescore
- 2026-06-06 13:46 UTCEPSS rescore
- 2026-06-05 22:45 UTCEPSS rescore
- 2026-06-05 06:09 UTCEPSS rescore
- 2026-06-05 06:09 UTCEPSS rescore
- 2026-06-04 13:11 UTCEPSS rescore
- 2026-06-04 13:11 UTCEPSS rescore
- 2026-06-02 20:11 UTCEPSS rescore
- 2026-06-02 20:11 UTCEPSS rescore
- 2026-06-02 20:11 UTCEPSS rescore
- 2026-06-01 13:50 UTCEPSS rescore
- 2026-06-01 13:50 UTCEPSS rescore
- 2026-06-01 13:50 UTCEPSS rescore
- 2026-05-31 22:29 UTCEPSS rescore
- 2026-05-31 22:29 UTCEPSS rescore
- 2026-05-31 00:15 UTCEPSS rescore
- 2026-05-31 00:15 UTCEPSS rescore
- 2026-05-29 13:42 UTCEPSS rescore
- 2026-05-28 13:43 UTCEPSS rescore
- 2026-05-28 13:43 UTCEPSS rescore
- 2026-05-28 13:43 UTCEPSS rescore
- 2026-05-27 13:39 UTCEPSS rescore
- 2026-05-27 13:39 UTCEPSS rescore
- 2026-05-26 13:43 UTCEPSS rescore
- 2026-05-26 07:17 UTCEPSS rescore
- 2026-05-26 07:17 UTCEPSS rescore
- 2026-05-26 01:25 UTCEG score recompute
- 2026-05-26 01:25 UTCVendor advisory
Frequently asked(5)
What is CVE-2022-24761?
When was CVE-2022-24761 disclosed?
Is CVE-2022-24761 actively exploited?
What is the CVSS score of CVE-2022-24761?
How do I remediate CVE-2022-24761?
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