Penpot: Missing authorization in chunked-upload assembly lets another authenticated user consume a victim's upload session

CISA KEV is observed exploitation evidence. FIRST EPSS is a dated prediction of exploitation in the next 30 days. Missing scores are unknown. This collector requests predictions only for explicit CVE aliases in the public NuGet archive; Microsoft release views retain their existing prediction scope.

No collected risk observation for these identifiers. This does not establish absence of exploitation or a zero probability.

Penpot is an open-source design and prototyping platform. Prior to 2.18.0, assemble-chunks retrieves an upload session using only its session ID, while upload-chunk correctly scopes the lookup to the authenticated profile. An authenticated user who obtains another user's live, completed upload-session UUID can assemble the victim's chunks into the attacker's own file, team font, or project import, disclosing the uploaded bytes and deleting the victim's pending session. This issue is fixed in version 2.18.0.

Source published

5 Oct 2026 20:04:22 UTC

Source modified

5 Oct 2026 20:40:42 UTC

Observed here

23 Oct 2026 15:48:27 UTC

Source terms

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CVSS 3.1 · 5.9 CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:L