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.

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.

EPSS: 0.003 (16.4th percentile) — read the EPSS interpretation.

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.

Affected products

Papermark — versions 0

Weakness classification (CWE)

CWE-942 — Permissive Cross-domain Policy with Untrusted Domains

References

disclosure@vulncheck.com (issue-tracking)
disclosure@vulncheck.com (issue-tracking, technical-description)
disclosure@vulncheck.com (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.