Vulnerability · CVE-2025-47278
Flask is a web server gateway interface (WSGI) web application framework.
Published May 13, 2025 · corrected/updated May 13, 2025 · pallets Flask · evidence confidence high
Flask is a web server gateway interface (WSGI) web application framework. In Flask 3.1.0, the way fallback key configuration was handled resulted in the last fallback key being used for signing, rather than the current signing key. Signing is provided by the library. A list of keys can be passed, and it expects the last (top) key in the list to be the most recent key, and uses that for signing. Flask was incorrectly constructing that list in reverse, passing the signing key first. Sites that have opted-in to use key rotation by setting care likely to unexpectedly be signing their sessions with
Grounded briefings
Catalog interpretations for three audiences. Each brief cites ingested metadata and the original advisories below. They are not independent research and they do not invent exploit steps.
Executive
CVE-2025-47278 is a low public vulnerability record for pallets Flask. It is not currently listed in the CISA Known Exploited catalog. Check the linked vendor or CERT advisories for patch status. This summary is a catalog interpretation of the ingested metadata and cites the original advisories below.
System administrator
Identify whether pallets Flask is in your estate, then compare installed versions with the affected ranges. Affected packages or ranges on record: pallets Flask = 3.1.0 (= 3.1.0). Check the linked vendor or CERT advisories for patch status. Prefer the vendor or distribution advisory linked in Sources before changing production systems. This is a catalog interpretation, not a runbook.
Security analyst
Signals on file: CVSS 1.8, EPSS 19.0%. It is not currently listed in the CISA Known Exploited catalog. Sources contributing to this record: euvd. Public exploit references, when present, are outbound links only and are not proof of active exploitation. This is a catalog interpretation of stored metadata.
Exploitation and remediation
Exploitation evidence
Not listed as known exploited in CISA KEV. Not in CISA KEV or VulnCheck KEV.
Patch and remediation
No required-action text is stored yet. Use the vendor or CERT links in Sources for patch availability.
Safe detection guidance
Compare installed versions with the affected ranges below and verify the advisory from the original publisher. This site stores metadata and outbound links only; it does not ship exploit code or proof-of-concept payloads.
Code
The project this record applies to. Exploit listings stay in References.
Timeline
Detection, updates, and resolution for this record.
May 13, 2025 · EUVD
Detected
Flask is a web server gateway interface (WSGI) web application framework. In Flask 3.1.0, the way fallback key configuration was handled resulted in the last fallback key being used for signing, rather than the current signing key. Signing is provided by the library. A list of keys can be passed, and it expects the last (top) key in the list to be the most recent key, and uses that for signing. Fl
May 13, 2025 · EUVD
Updated
Flask is a web server gateway interface (WSGI) web application framework. In Flask 3.1.0, the way fallback key configuration was handled resulted in the last fallback key being used for signing, rather than the current signing key. Signing is provided by the library. A list of keys can be passed, and it expects the last (top) key in the list to be the most recent key, and uses that for signing. Fl
Affected
- vendor pallets Flask = 3.1.0= 3.1.0
Sources
- EUVDVulnerability recordEUVD-2025-14386
Flask is a web server gateway interface (WSGI) web application framework. In Flask 3.1.0, the way fallback key configuration was handled resulted in the last fallback key being used for signing, rather than the current signing key. Signing is provided by the library. A list of ke
euvd.enisa.europa.eu