Cyber Resilience

CVE-2023-49438

Open Redirect in Flask-Security-Too Project Flask-Security-Too ≤ 5.3.2

Public PoCOpen Redirect
Published
26 December 2023
Modified
04 November 2025
Patch / advisory
CVSS Score v3.1 6.1
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
EPSS Score 0.011 63th percentile
Risk Priority 57 floored blend · peak EPSS

CVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.

Summary

CVE-2023-49438 is a medium-severity Open Redirect (CWE-601) vulnerability in Flask-Security-Too Project Flask-Security-Too. Its CVSS base score is 6.1 (Medium).

Operationally, exploitation aligns with the MITRE ATT&CK technique Phishing (T1566); ranked in the top 37% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

Deeper analysis AI-assisted summary

Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.

CVE-2023-49438 is an open redirect vulnerability affecting the Flask-Security-Too Python package at version 5.3.2 and earlier. The flaw resides in the handling of the next query parameter on the /login and /register routes, enabling redirection to arbitrary destinations.

An unauthenticated attacker can exploit the issue by supplying a crafted URL containing a malicious next parameter value. Successful abuse redirects a victim user who follows the link to an attacker-controlled site, which may be leveraged for phishing or further social-engineering attacks.

Public references include the upstream Flask-Security repository, a dedicated proof-of-concept repository, and a Fedora package-announce mailing-list posting; these sources constitute the primary locations for any subsequent patch or advisory information.

The associated EPSS score stands at 0.1407 with an identical recorded peak, indicating no material post-disclosure increase in observed exploitation interest.

OWASP Top 10 for Web (2025)

EU & UK References

Vulnerability Data

An open redirect vulnerability in the python package Flask-Security-Too <=5.3.2 allows attackers to redirect unsuspecting users to malicious sites via a crafted URL by abusing the ?next parameter on the /login and /register routes.

CWE(s)

Related Threats

MITRE ATT&CK Enterprise Techniques

T1566 Phishing Initial Access
Adversaries may send phishing messages to gain access to victim systems.
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2024-12990Shared CWE-601
CVE-2025-55625Shared CWE-601
CVE-2023-37624Shared CWE-601
CVE-2025-53535Shared CWE-601
CVE-2024-7941Shared CWE-601
CVE-2025-42985Shared CWE-601
CVE-2026-11477Shared CWE-601
CVE-2026-79662Shared CWE-601
CVE-2023-35883Shared CWE-601
CVE-2025-50736Shared CWE-601

Affected Assets

flask-security-too project
flask-security-too
≤ 5.3.2

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

Detect
Catch it (NIST detect / respond)

Harden
Shrink the surface (DISA STIG)

Validate
Prove the fix (OWASP ASVS)
  • V3.7.2

Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

addresses: CWE-601

Security awareness includes verifying URLs and avoiding untrusted redirects that lead to malicious sites.

addresses: CWE-601

Validates redirect targets and URLs to ensure they conform to allowed destinations.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.PS-06 mostly match
prevents

Secure SDLC practices directly require input validation and untrusted-redirect controls that prevent CWE-601.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

mitigates

Preventing access to attacker-controlled or malicious sites stops users from being redirected to untrusted locations via open-redirect or phishing links.

References