CVE-2026-44889
CVE-2026-44889 is a medium-severity vulnerability in Pylonsproject Webob with a CVSS 3.x base score of 6.1. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-601.
Key facts
- Severity: Medium (CVSS 3.x base score 6.1)
- EPSS exploit prediction: 0% (6th percentile)
- Actively exploited: Not listed in CISA KEV
- EU (EUVD) id: EUVD-2026-38391
- Weakness: CWE-601
- Affected product: Pylonsproject Webob
- Published:
- Last modified:
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.
Frequently asked questions
- What is CVE-2026-44889?
- 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.
- How severe is CVE-2026-44889?
- CVE-2026-44889 has a CVSS 3.x base score of 6.1, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is low, integrity low, and availability none.
- Is CVE-2026-44889 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (6th percentile), an estimate of the probability of exploitation in the next 30 days.
- What products are affected by CVE-2026-44889?
- CVE-2026-44889 affects Pylonsproject Webob. See the affected-products list for the exact vulnerable versions.
- How do I fix CVE-2026-44889?
- Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
- Does CVE-2026-44889 have an EU (EUVD) identifier?
- Yes. CVE-2026-44889 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-38391.
- When was CVE-2026-44889 published?
- CVE-2026-44889 was published on 2026-06-22 and last updated on 2026-06-26.
References
Affected products (1)
- cpe:2.3:a:pylonsproject:webob:*:*:*:*:*:*:*:*
More vulnerabilities in Pylonsproject Webob
- CVE-2024-42353 — Medium (CVSS 6.1): WebOb provides objects for HTTP requests and responses. When WebOb normalizes the HTTP Location header to include the…
All CVEs affecting Pylonsproject Webob →
Other CWE-601 (Open Redirect) vulnerabilities
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