GHSA-mg3v-6m49-jhp3 is a medium-severity (CVSS 6.1) Open Redirect vulnerability in webob. 1 public exploit reference exists, so weaponization risk is real. A fix is available for webob — see the affected versions and patch details below.
WebOb's location header normalization during redirect leads to open redirect
Exploitation Status
No confirmed exploitation observed yet
- 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-mg3v-6m49-jhp3.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
GHSA-mg3v-6m49-jhp3 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 377,166 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
webobReal-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
When WebOb normalizes the HTTP Location header to include the request hostname, it does so by parsing the URL that the user is to be redirected to with Python's urlparse, and joining it to the base URL. urlparse however treats a // at the start of a string as a URI without a scheme, and then treats the next part as the hostname. urljoin will then use that hostname from the second part as the hostname replacing the original one from the request.
>>> parse.urlparse("//example.com/test/path")
ParseResult(scheme='', netloc='example.com', path='/test/path', params='', query='', fragment='')
WebOb uses urljoin to take the request URI and joining the redirect location, so assuming the request URI is: https://example.org//example.com/some/path, and the URL to redirect to (for example by adding a slash automatically) is //example.com/some/path/ that gets turned by urljoin into:
>>> parse.urljoin("https://example.org//attacker.com/some/path", "//attacker.com/some/path/")
'https://attacker.com/some/path/'
Which redirects from example.org where we want the user to stay to attacker.com
Patches
This issue is patched in WebOb 1.8.8
Older versions of WebOb continue to be vulnerable to this issue, and should be avoided.
Workarounds
Any use of the Response class that includes a location can be rewritten to make sure to always pass a full URI that includes the hostname to redirect the user to.
Thanks
- Sara Gao
This issue was reported via the Pylons Project Security List
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | webob | all versions | 1.8.8pip install --upgrade 'webob==1.8.8' |
Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for webob, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update webob to 1.8.8 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-mg3v-6m49-jhp3 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.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like GHSA-mg3v-6m49-jhp3 can be triaged on real exposure rather than presence alone.
Tailored to GHSA-mg3v-6m49-jhp3. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
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.
| Product | Fixed in | Advisory |
|---|---|---|
| Ironic content for Red Hat OpenShift Container Platform 4.13 | python-webob-0:1.8.8-2.el9 | RHSA-2024:7941 |
| Red Hat Ceph Storage 7.1 | oath-toolkit-0:2.6.12-1.el8cp | RHSA-2025:4664 |
| Red Hat Ceph Storage 8.1 | oath-toolkit-0:2.6.12-1.el9cp | RHSA-2025:9775 |
| Red Hat OpenShift Container Platform 4.12 | openshift4/ose-ironic-rhel9:v4.12.0-202410011359.p0.g4d1b61e.assembly.stream.el9 | RHSA-2024:7590 |
| Red Hat OpenShift Container Platform 4.14 | python-webob-0:1.8.8-2.el9 | RHSA-2024:7187 |
| Red Hat OpenShift Container Platform 4.15 | python-webob-0:1.8.8-2.el9 | RHSA-2024:7182 |
| Red Hat OpenShift Container Platform 4.16 | python-webob-0:1.8.8-2.el9 | RHSA-2024:6827 |
| Red Hat OpenStack Platform 17.1 for RHEL 8 | python-webob-0:1.8.7-2.1.el8ost | RHSA-2024:9989 |
Frequently Asked Questions
Is GHSA-mg3v-6m49-jhp3 in your dependencies?
O3 Security finds GHSA-mg3v-6m49-jhp3 across PyPI dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.