Vulnerability · Published Jun 22, 2026 · Assigned by GitHub_M
CVE-2026-44889WebOb: Location header normalization during redirect leads to open redirect
Medium 6.1
In plain English
A medium-severity open redirect in webob from Pylons. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 19% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
WebOb provides objects for HTTP requests and responses. Prior to 1.8.10, the normalization of the HTTP Location header during a redirect is vulnerable to an open redirect: WebOb joins the redirect target to the request URI using Python's urljoin, and since Python 3.10 the underlying urlsplit strips ASCII tab, carriage return, and newline characters before parsing, so a redirect target containing such characters can be reinterpreted as a protocol-relative URL whose authority is an attacker-controlled host. This bypasses the CVE-2024-42353 fix that escaped a leading double slash, allowing an attacker who influences the redirect location to send users to an arbitrary external site instead of the intended one. This vulnerability is fixed in 1.8.10.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | python-webob | no fix listed | DEBIAN-CVE-2026-44889 |
| Debian:13 | python-webob | 1:1.8.10-0+deb13u1 | DEBIAN-CVE-2026-44889 |
| Debian:14 | python-webob | 1:1.8.10-1 | DEBIAN-CVE-2026-44889 |
| PyPI | webob | 1.8.10 | GHSA-fh3h-vg37-cc95 |
| PyPI | webob | 1.8.10 | PYSEC-2026-251 |
| Ubuntu:22.04:LTS | python-webob | 1:1.8.6-1.1ubuntu0.2 | USN-8759-1 |
| Ubuntu:22.04:LTS | python-webob | 1:1.8.6-1.1ubuntu0.2 | UBUNTU-CVE-2026-44889 |
| Ubuntu:24.04:LTS | python-webob | 1:1.8.7-1ubuntu0.1.24.04.2 | USN-8759-1 |
| Ubuntu:24.04:LTS | python-webob | 1:1.8.7-1ubuntu0.1.24.04.2 | UBUNTU-CVE-2026-44889 |
| Ubuntu:25.10 | python-webob | no fix listed | UBUNTU-CVE-2026-44889 |
| Ubuntu:26.04:LTS | python-webob | 1:1.8.9-1ubuntu0.1 | UBUNTU-CVE-2026-44889 |
| Ubuntu:26.04:LTS | python-webob | 1:1.8.9-1ubuntu0.1 | USN-8759-1 |
Affected products (as reported)
Weakness: CWE-601 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
References
- https://github.com/Pylons/webob/security/advisories/GHSA-fh3h-vg37-cc95 x_refsource_CONFIRM