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WebobApplication · Pylonsproject

CVE-2026-44889

MEDIUM · 6.1 CVSS v3.1 Published 2026-06-22
Fix available
A fix is available. Upgrade to 1.8.10 or later.
See remediation →
68/100
Remediation priority · Elevated
Remotely reachable No privileges

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
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.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

WebOb versions prior to 1.8.10 contain an open redirect vulnerability in HTTP Location header normalization. The library uses Python's urljoin to combine redirect targets with the request URI, but Python 3.10's urlsplit silently strips ASCII tab, carriage return, and newline characters before parsing. This allows attackers to inject control characters that transform the redirect target into a protocol-relative URL with an attacker-controlled authority, bypassing the CVE-2024-42353 fix.

MitigationUpgrade WebOb to version 1.8.10 or later to patch the vulnerability. If upgrading is not immediately possible, audit all code paths that generate HTTP redirects to validate that redirect targets cannot contain control characters.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
WebobApplication
Affected:< 1.8.10

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
Required
Scope
Changed
Confidentiality
Low
Integrity
Low
Availability
None

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Check installed WebOb version
    Run `pip show WebOb` or `python -c "import webob; print(webob.__version__)"`
    Affected if Version is lower than 1.8.10
  2. Check Python version
    Run `python --version` or `python -c "import sys; print(sys.version)"`
    Affected if Python version is 3.10 or higher (required for urlsplit to strip control characters)
  3. Identify if application uses WebOb redirect handling
    Search codebase for usage of webob.redirect, webob.exc.HTTPFound, or Response(location=...) patterns
    Affected if Application uses WebOb to set Location headers in HTTP responses
  4. Check if redirect targets accept user input
    Audit code paths that set Location headers and determine if any user-supplied data flows into the redirect target
    Affected if User-controlled input can influence the redirect target passed to WebOb's redirect functionality

You are affected if WebOb version is below 1.8.10, Python 3.10+ is in use, and your application passes user-supplied data to WebOb's redirect/Location header functionality.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 1.8.10 or later
Fixed in 1.8.10
Interim mitigation

Upgrade WebOb to version 1.8.10 or later to patch the vulnerability. If upgrading is not immediately possible, audit all code paths that generate HTTP redirects to validate that redirect targets cannot contain control characters.

Recommended fix High confidence

WebOb 1.8.10

  1. Upgrade WebOb to version 1.8.10 or later using your package manager (e.g., pip install WebOb>=1.8.10)
  2. Verify the upgrade was successful by checking the installed version (e.g., python -c 'import webob; print(webob.__version__)')
  3. Rebuild and redeploy any applications or services that depend on WebOb to ensure they use the patched version
  4. If your application uses a lock file (requirements.txt, Pipfile.lock, poetry.lock), regenerate it to lock the fixed version

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Webob Scoped from the published advisory
  • Consultation2.0 h
  • Implementation1.0 h
  • Testing4.0 h
  • Review / QA2.0 h
9.0 hours of engineering $1,540
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,464.

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-44889 in production — separate from our analysis above.

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
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  • No spam, self-promotion, credentials, or personal data