CVE-2026-44889 | WebOb: Location header normalization during redirect leads to open redirect

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.

Published: 2026-06-22 Last update: 2026-06-26 Assigner: [email protected] Source: [email protected]
NVD Status：Analyzed，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2026-44889 is rated Low Risk (26.8/100): CVSS Medium severity, with low exploitation likelihood (EPSS 0.17%). Monitor for updates and reassess as exploit intelligence or EPSS changes.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2026-44889

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-23 0.04% 0.17% +0.13%
2 2026-06-12 — 0.04% —

Full EPSS history (2 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2026-44889

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
6.1 3.1 MEDIUM
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:R)
A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:C)
Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:L)
Some sensitive info could get out, but not a total data dump.
Integrity (I:L)
Attackers could change some data, but it’s limited—not everything goes.
Availability (A:N)
Service keeps running; no real outage angle.
 2.8 2.7 [email protected]

Weakness enumeration for CVE-2026-44889

GitHub Security Advisory for CVE-2026-44889

GHSA-fh3h-vg37-cc95 · Severity: medium · Ecosystem: pip — WebOb: Location header normalization during redirect leads to open redirect - again

OS Trackers for CVE-2026-44889

vendor priority summary link
debian not yet assigned CVE-2026-44889 not yet assigned priority: Debian including 1 source packages (python-webob), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 3, open 2. https://security-tracker.debian.org/tracker/CVE-2026-44889
suse medium CVE-2026-44889 severity moderate: SUSE including 7 source package names (python-WebOb, python-WebOb-doc-1.8.10-1.1, …), 8 product×package rows across 5 product lines (SUSE Linux Enterprise Module for Basesystem 15 SP7, SUSE Linux Enterprise Module for Package Hub 15 SP7, … (5 product lines)): Fixed 4, First Fixed 3, Known Not Affected 1. https://www.suse.com/security/cve/CVE-2026-44889/
ubuntu medium CVE-2026-44889 medium priority: Ubuntu including 1 source packages (python-webob), 8 status rows across 8 suites (bionic, focal, jammy, noble, questing, resolute, upstream, xenial): needs-triage 8. https://ubuntu.com/security/CVE-2026-44889

Affected software / configurations for CVE-2026-44889

Vendor Product Version Raw CPE
pylonsproject webob < 1.8.10 cpe:2.3:a:pylonsproject:webob:*:*:*:*:*:*:*:*

References for CVE-2026-44889

cvelogic Threat Intelligence