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Fencer Vulns
medium 6.1

CVE-2026-44889 json

WebOb: Location header normalization during redirect leads to open redirect

published 2026-06-04 5 mo ago modified 2026-10-25 14 d ago also EUVD-2026-38391 , GHSA-fh3h-vg37-cc95 , PYSEC-2026-251

cvss
6.1
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 19%
public exploits
0
none known

Summary

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.

Patch / fix

  • pypi webob 1.8.10
  • pylonsproject webob 1.8.10
  • python-webob Debian 13 1:1.8.10-0+deb13u1
  • python-webob Debian 14 1:1.8.10-1

debian advisories DEBIAN-CVE-2026-44889

  • python-webob Ubuntu 22.04 LTS 1:1.8.6-1.1ubuntu0.2
  • python-webob Ubuntu 24.04 LTS 1:1.8.7-1ubuntu0.1.24.04.2
  • python-webob Ubuntu 26.04 LTS 1:1.8.9-1ubuntu0.1
  • python-webob Ubuntu Pro 16.04 LTS 1.5.1-1ubuntu0.1~esm2
  • python-webob Ubuntu Pro 18.04 LTS 1:1.7.3-2ubuntu0.1~esm2
  • python-webob Ubuntu Pro 20.04 LTS 1:1.8.5-2ubuntu0.1+esm1

ubuntu advisories UBUNTU-CVE-2026-44889

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • python-WebOb SLE Module for Package Hub 15 SP7, SLE Module for Basesystem 15 SP7 1.7.4-150000.3.6.1
  • python-soupsieve SLES for SAP applications 16.0, SLES 16.0 2.6-160000.3.1
  • python-WebOb SLES for SAP applications 16.0, SLES 16.0 1.8.9-160000.3.1
  • python-Markdown SLES for SAP applications 16.0, SLES 16.0 3.8.2-160000.3.1
  • python-PyGithub SLES for SAP applications 16.0, SLES 16.0 2.6.1-160000.3.1
  • python-handy-archives SLES for SAP applications 16.0, SLES 16.0 0.2.0-160000.3.1
  • python-apache-libcloud SLES for SAP applications 16.0, SLES 16.0 3.8.0-160000.3.1

suse advisories SUSE-SU-2026:2982-1SUSE-SU-2026:22370-1

  • python-soupsieve openSUSE Leap 16.0 2.6-160000.3.1
  • python-WebOb openSUSE Leap 16.0 1.8.9-160000.3.1
  • python-joblib openSUSE Leap 16.0 1.5.2-160000.1.1
  • python-Markdown openSUSE Leap 16.0 3.8.2-160000.3.1
  • python-PyGithub openSUSE Leap 16.0 2.6.1-160000.3.1
  • python-handy-archives openSUSE Leap 16.0 0.2.0-160000.3.1
  • python-apache-libcloud openSUSE Leap 16.0 3.8.0-160000.3.1
  • python-WebOb openSUSE Tumbleweed 1.8.10-1.1

opensuse advisories openSUSE-SU-2026:21063-1openSUSE-SU-2026:11041-1

  • python-webob Azure Linux 3.0 1.8.10-1

azure linux advisories AZL-91362

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-44889 updated cvss 6.1

webob: python-webob: WebOb: Open Redirect vulnerability via HTTP Location header normalization

  • Red Hat Enterprise Linux 6 python-webob
    affected: workaround, no fix planned “Out of support scope”
  • Red Hat Ceph Storage 4 python2-webob, python3-webob Red Hat Enterprise Linux 7 python-webob Red Hat OpenShift Container Platform 4 python2-webob, python3-webob Red Hat OpenStack Platform 16.2 python3-webob Red Hat OpenStack Platform 17.1 python-webob, python3-webob Red Hat OpenStack Platform 18.0 python-webob
    +1 more products
    Red Hat Quay 3 quay/quay-rhel8, quay/quay-rhel9
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
4 mo ago

Exploit prediction

0.27% chance of exploitation in the next 30 days, higher than 19% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 6.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
GitHub 3.1 6.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
OSV 3.1 6.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

Affected packages

ecosystem package affected fixed in
pypi webob
<1.8.10
1.8.10

Affected products

  • Pylons webob

Classification

Weakness
  • CWE-601 URL Redirection to Untrusted Site

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.