CVE-2026-33057: Mesop is a Python-based UI framework that allows users to build web applications

Q: How do I fix CVE-2026-33057?

mesop: upgrade to 1.2.3. Exact commands for each OS are on this page.

Q: Is CVE-2026-33057 being exploited?

CVE-2026-33057 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2026-33057 affect?

CVE-2026-33057 affects mesop. Severity is critical (CVSS 9.8). Mesop is a Python-based UI framework that allows users to build web applications. In versions 1.2.2 and below, an explicit web endpoint inside the ai/ testing module infrastructure directly ingests untrusted Python code strings unconditiona

Q: How urgent is CVE-2026-33057?

Priority 68/100. Critical severity; EPSS top 7%: very likely to be exploited; CISA SSVC: public proof of concept; CISA SSVC: automatable with total technical impact; Remotely exploitable, no login, no user action

This week

CRITICAL 9.8REMOTEUPGRADE

CVE-2026-33057 is a critical-severity flaw (CVSS 9.8) affecting mesop. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Mesop is a Python-based UI framework that allows users to build web applications. In versions 1.2.2 and below, an explicit web endpoint inside the ai/ testing module infrastructure directly ingests untrusted Python code strings unconditionally without authentication measures, yielding standard Unrestricted Remote Code Execution. Any individual capable of routing HTTP logic to this server block will gain explicit host-machine command rights. The A

Why this priority

Critical severity
EPSS top 7%: very likely to be exploited
CISA SSVC: public proof of concept
CISA SSVC: automatable with total technical impact
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	9.8 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	5.3% (top 7%)
CISA exploited list	No
Weakness	CWE-94
Published	2026-03-20
Last modified	2026-06-17

Publisher (CNA): GitHub, Inc. · Vendor: mesop-dev

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-03-20 08:16 UTCPublished CVE record published
2026-06-17 10:36 UTCUpdated Record last modified

mesop-dev mesop UPGRADE

Affected: < 1.2.3

Fixed in: 1.2.3

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy mesop || rpm -q mesop || mesop --version

2. UPGRADE to 1.2.3 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade mesop

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade mesop

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

Exact fixes by distribution

Python (pip) · mesop · FIXED · 1.2.3 · vulnerable: <= 1.2.2 · source

pip install --upgrade "mesop>=1.2.3" pip show mesop

Fedora ELN · fonttools · FIXED · 4.68.0-1.eln159 · FEDORA-2026-37fa4b964c · source

sudo dnf upgrade --advisory=FEDORA-2026-37fa4b964c

Fedora 46 · fonttools · FIXED · 4.68.0-1.fc46 · FEDORA-2026-65d6c01c75 · source

sudo dnf upgrade --advisory=FEDORA-2026-65d6c01c75

Public exploits and detection

Public code exists for this CVE. Treat unpatched systems as at risk, and only run PoCs in a lab.

GitHub PoC: hackpatato/CVE-2026-33057---Mesop-Unauthenticated-RCE-PoC-and-yara-rules (1 stars)
Write-up: github.com/mesop-dev/mesop/security/advisories/GHSA-gjgx-rvqr-6w6v
Nuclei scan template: Mesop AI Sandbox <= 1.2.2 - Remote Code Execution

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-33057?

mesop: upgrade to 1.2.3. Exact commands for each OS are on this page.

Is CVE-2026-33057 being exploited?

CVE-2026-33057 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-33057 affect?

CVE-2026-33057 affects mesop. Severity is critical (CVSS 9.8). Mesop is a Python-based UI framework that allows users to build web applications. In versions 1.2.2 and below, an explicit web endpoint inside the ai/ testing module infrastructure directly ingests untrusted Python code strings unconditiona

How urgent is CVE-2026-33057?

Priority 68/100. Critical severity; EPSS top 7%: very likely to be exploited; CISA SSVC: public proof of concept; CISA SSVC: automatable with total technical impact; Remotely exploitable, no login, no user action

Software pages

Python vulnerabilities

Related CVEs

CVE-2026-34824 HIGH 7.5 UPGRADE Mesop is a Python-based UI framework that allows users to build web applications
CVE-2026-33054 CRITICAL 10.0 UPGRADE Mesop is a Python-based UI framework that allows users to build web applications

References

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