StackPrism

PyPI package

Flask 1.1.2 vulnerabilities, and the version that fixes all of them

Flask 1.1.2 has 2 known vulnerabilities (1 rated high or critical); 3.1.3 fixes all of them.

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

Known vulnerabilities
2
1 rated high or critical
Released
Apr 3, 2020
Latest is 3.1.3
Licence
BSD-3-Clause
OpenSSF Scorecard
7.1/10
pallets/flask (opens in a new tab)
Pulls in
5 packages
Resolved by deps.dev

What to upgrade to

3.1.3 is the closest release with no known vulnerabilities.

  • 1.1.4

    Newest 1.x release. Released May 14, 2021.

    2 known vulnerabilities, worst rated warning

  • 3.1.3Upgrade to this

    Fixes all 2 known vulnerabilities and the latest release. Released Feb 19, 2026.

    No known vulnerabilities

3.1.3 came out on Feb 19, 2026. A coding agent trained before then doesn’t know it exists, so it may suggest an older release. AI knowledge cutoff dates

Hand the fix to your coding agent

One task with the upgrade, the file to change and why. Paste it into Claude Code, Cursor or Codex.

Findings

Every advisory for Flask 1.1.2

Known exploited first (CISA KEV), then by how likely they are to be exploited (FIRST EPSS), then by severity. Each id links to its OSV.dev record.

  1. CriticalCVE-2023-30861 on OSV.dev (opens in a new tab)GHSA-m2qf-hxjv-5gpqEPSS: top 31%

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

    Fixed in 2.2.5. Published May 1, 2023.

  2. LowCVE-2026-27205 on OSV.dev (opens in a new tab)GHSA-68rp-wp8r-4726EPSS: top 64%

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

    Fixed in 3.1.3. Published Feb 19, 2026.

Is Flask the only one?

Paste a public GitHub repo or drop your requirements.txt or pyproject.toml and see every vulnerable, end-of-life or deprecated dependency, with one fix task. Free, no sign-up.

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How this page is checked

StackPrism asks OSV.dev which advisories affect exactly Flask 1.1.2, merges duplicates filed under several ids, and ranks them with CISA’s Known Exploited Vulnerabilities list and FIRST EPSS. Release dates and deprecation come from deps.dev and PyPI. No AI writes this page: every sentence comes from that data, refreshed every few hours.

Last checked against PyPI, OSV.dev, deps.dev, CISA KEV and FIRST EPSS.