Eventlet affected by HTTP request smuggling in unparsed trailersGHSA-hw6f-rjfj-j7j7
Fix: eventlet/eventlet#1062GHSA-hw6f-rjfj-j7j7 is a CWE-444 vulnerability in eventlet. A fix is available for eventlet — see the affected versions and patch details below.
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.
- 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 GHSA-hw6f-rjfj-j7j7.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
Real-World Exposure
eventletReal-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
The Eventlet WSGI parser is vulnerable to HTTP Request Smuggling due to improper handling of HTTP trailer sections.
This vulnerability could enable attackers to:
- Bypass front-end security controls
- Launch targeted attacks against active site users
- Poison web caches
Patches
Problem has been patched in eventlet 0.40.3.
The patch just drops trailers. If a backend behind eventlet.wsgi proxy requires trailers, then this patch BREAKS your setup.
Workarounds
Do not use eventlet.wsgi facing untrusted clients.
References
- Patch https://github.com/eventlet/eventlet/pull/1062
- This issue is similar to https://github.com/advisories/GHSA-9548-qrrj-x5pj
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | eventlet | all versions | 0.40.3pip install --upgrade 'eventlet==0.40.3' |
Affected Products
eventleteventletDetection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for eventlet, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update eventlet to 0.40.3 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-hw6f-rjfj-j7j7 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.
Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.Source: Red Hat security advisory for GHSA-hw6f-rjfj-j7j7 (CC BY 4.0)
| Product | Fixed in | Advisory |
|---|---|---|
| Red Hat OpenStack Services on OpenShift 18.0 | python-eventlet-0:0.33.1-7.el9ost | RHSA-2026:1959 |
| Red Hat OpenShift Container Platform 4.12 | openshift4/ose-ironic-agent-rhel9:1772155648 | RHSA-2026:3870 |
| Red Hat OpenShift Container Platform 4.13 | openshift4/ose-ironic-agent-rhel9:1771853308 | RHSA-2026:3422 |
| Red Hat OpenShift Container Platform 4.14 | openshift4/ose-ironic-agent-rhel9:1770733671 | RHSA-2026:2990 |
| Red Hat OpenShift Container Platform 4.15 | openshift4/ose-ironic-agent-rhel9:1769530180 | RHSA-2026:1549 |
| Red Hat OpenShift Container Platform 4.16 | openshift4/ose-ironic-agent-rhel9:1770654140 | RHSA-2026:2661 |
| Red Hat OpenShift Container Platform 4.17 | openshift4/ose-ironic-agent-rhel9:1769561620 | RHSA-2026:1577 |
| Red Hat OpenShift Container Platform 4.18 | openshift4/ose-ironic-agent-rhel9:1768710367 | RHSA-2026:1062 |
Frequently Asked Questions
Is GHSA-hw6f-rjfj-j7j7 in your dependencies?
Find it across PyPI, including transitive dependencies.