How severe is CVE-2026-33054?

CVE-2026-33054 has a CVSS 3.x base score of 10.0, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2026-33054 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (49th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-33054?

CVE-2026-33054 affects Mesop-dev Mesop. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-33054?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

Does CVE-2026-33054 have an EU (EUVD) identifier?

Yes. CVE-2026-33054 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-13594.

When was CVE-2026-33054 published?

CVE-2026-33054 was published on 2026-03-20 and last updated on 2026-06-17.

CVE-2026-33054

CVE-2026-33054 is a critical-severity vulnerability in Mesop-dev Mesop with a CVSS 3.x base score of 10.0. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-22.

Key facts

Severity: Critical (CVSS 3.x base score 10.0)
EPSS exploit prediction: 1% (49th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-13594
Weakness: CWE-22
Affected product: Mesop-dev Mesop
Published: 2026-03-20
Last modified: 2026-06-17

Description

Mesop is a Python-based UI framework that allows users to build web applications. Versions 1.2.2 and below contain a Path Traversal vulnerability that allows any user supplying an untrusted state_token through the UI stream payload to arbitrarily target files on the disk under the standard file-based runtime backend. This can result in application denial of service (via crash loops when reading non-msgpack target files as configurations), or arbitrary file manipulation. This vulnerability heavily exposes systems hosted utilizing FileStateSessionBackend. Unauthorized malicious actors could interact with arbitrary payloads overwriting or explicitly removing underlying service resources natively outside the application bounds. This issue has been fixed in version 1.2.3.

Frequently asked questions

What is CVE-2026-33054?: Mesop is a Python-based UI framework that allows users to build web applications. Versions 1.2.2 and below contain a Path Traversal vulnerability that allows any user supplying an untrusted state_token through the UI stream payload to arbitrarily target files on the disk under the standard file-based runtime backend. This can result in application denial of service (via crash loops when reading non-msgpack target files as configurations), or arbitrary file manipulation. This vulnerability heavily exposes systems hosted utilizing FileStateSessionBackend. Unauthorized malicious actors could interact with arbitrary payloads overwriting or explicitly removing underlying service resources natively outside the application bounds. This issue has been fixed in version 1.2.3.
How severe is CVE-2026-33054?: CVE-2026-33054 has a CVSS 3.x base score of 10.0, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2026-33054 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (49th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-33054?: CVE-2026-33054 affects Mesop-dev Mesop. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-33054?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
Does CVE-2026-33054 have an EU (EUVD) identifier?: Yes. CVE-2026-33054 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-13594.
When was CVE-2026-33054 published?: CVE-2026-33054 was published on 2026-03-20 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:mesop-dev:mesop:*:*:*:*:*:*:*:*

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