StackPrism

PyPI package

Flask vulnerabilities by version

The latest release, 3.1.3 (Feb 19, 2026), has no known vulnerabilities. 9 of the 10 most recent releases have known vulnerabilities. OSV.dev lists 5 advisories for Flask; the newest was published on Feb 19, 2026.

PyPI (opens in a new tab) describes it as “A simple framework for building complex web applications.”

Latest release
3.1.3
Feb 19, 2026, no known vulnerabilities
Downloads last week
40.1M
All versions, from pypistats.org
Advisories on OSV.dev
5
Newest Feb 19, 2026
Licence
BSD-3-Clause
OpenSSF Scorecard
7.1/10
pallets/flask (opens in a new tab)

Recent releases

PyPI doesn’t publish downloads per version, so these are the newest releases, each checked against OSV.dev. Open a version for its advisories and what to upgrade to.

VersionKnown vulnerabilities
3.1.3latestFeb 19, 2026No known vulnerabilities
3.1.2Aug 19, 20251 known vulnerability, worst rated low
3.1.1May 13, 20251 known vulnerability, worst rated low
3.1.0Nov 13, 20242 known vulnerabilities, worst rated low
3.0.3Apr 7, 20241 known vulnerability, worst rated low
3.0.2Feb 3, 20241 known vulnerability, worst rated low
3.0.1Jan 18, 20241 known vulnerability, worst rated low
3.0.0Sep 30, 20231 known vulnerability, worst rated low
2.3.3Aug 21, 20231 known vulnerability, worst rated low
2.2.5May 2, 20231 known vulnerability, worst rated low

Release lines

The newest release of each minor line, from the registry. Flask doesn’t publish support dates we can check.

LineNewest releaseReleased
3.13.1.3Feb 19, 2026
3.03.0.3Apr 7, 2024
2.32.3.3Aug 21, 2023
2.22.2.5May 2, 2023
2.12.1.3Jul 13, 2022
2.02.0.3Feb 14, 2022

Newest advisories

The 5 most recently published, with the versions each one affects.

  1. LowCVE-2026-27205 on OSV.dev (opens in a new tab)GHSA-68rp-wp8r-4726

    Flask session does not add `Vary: Cookie` header when accessed in some ways

    Affects < 3.1.3. Published Feb 19, 2026.

  2. LowCVE-2025-47278 on OSV.dev (opens in a new tab)GHSA-4grg-w6v8-c28g

    Flask uses fallback key instead of current signing key

    Affects >= 3.1.0, < 3.1.1. Published May 13, 2025.

  3. CriticalCVE-2023-30861 on OSV.dev (opens in a new tab)GHSA-m2qf-hxjv-5gpq

    Flask vulnerable to possible disclosure of permanent session cookie due to missing Vary: Cookie header

    Affects >= 2.3.0, < 2.3.2; < 2.2.5. Published May 1, 2023.

  4. CriticalCVE-2019-1010083 on OSV.dev (opens in a new tab)GHSA-5wv5-4vpf-pj6m

    Pallets Project Flask is vulnerable to Denial of Service via Unexpected memory usage

    Affects < 1.0. Published Jul 19, 2019.

  5. CriticalCVE-2018-1000656 on OSV.dev (opens in a new tab)GHSA-562c-5r94-xh97

    Flask is vulnerable to Denial of Service via incorrect encoding of JSON data

    Affects < 0.12.3. Published Aug 23, 2018.

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How this page is checked

StackPrism reads every OSV.dev advisory for Flask, merges duplicates filed under several ids, and asks OSV.dev which ones affect each version listed. Releases and their dates come from deps.dev, downloads from pypistats.org. No AI writes this page: every sentence comes from that data, refreshed every few hours.

Last checked against OSV.dev, CISA KEV, PyPI, pypistats.org and deps.dev.