Vulnerability in Papermark
CVE-2026-57957
Papermark through 0.22.0 contains a cross-origin resource sharing (CORS) misconfiguration vulnerability that allows unauthenticated remote attackers to perform credentialed cross-origin requests by exploiting the TUS-based viewer upload endpoint reflecting arbitrary request Origins with Access-Control-Allow-Credentials set to true. Attackers can lure authenticated victims to malicious pages that silently issue credentialed cross-origin requests to upload arbitrary files into victim datarooms and read credentialed responses.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 4.7 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:N/I:L/A:N.
EPSS exploit prediction
EPSS: 0.004 (35.4th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 35th percentile — 35.4% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.004 · newest: 0.004 · change: 0.000
Affected products
- Papermark — versions 0
Weakness classification (CWE)
References
- github.com/AstoKr/papermark/pull/1 (issue-tracking)
- github.com/papermark/papermark/issues/2178 (issue-tracking, technical-description)
- www.vulncheck.com/advisories/papermark-cors-misconfiguration-in-viewer-upload-e… (third-party-advisory)
Frequently asked questions
- What is CVE-2026-57957?
- CVE-2026-57957 is a medium-severity vulnerability in Papermark, classified under Permissive Cross-domain Policy with Untrusted Domains. CVSS score: 4.7/10. Published 2026-06-29.
- How severe is CVE-2026-57957?
- Medium severity. CVSS v3 base score is 4.7 out of 10.