How severe is CVE-2026-57957?

CVE-2026-57957 has a CVSS 3.x base score of 4.7, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is none, integrity low, and availability none.

Is CVE-2026-57957 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (16th percentile), an estimate of the probability of exploitation in the next 30 days.

How do I fix CVE-2026-57957?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2026-57957 published?

CVE-2026-57957 was published on 2026-06-29 and last updated on 2026-07-01.

CVE-2026-57957

CVE-2026-57957 is a medium-severity vulnerability with a CVSS 3.x base score of 4.7. 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-942.

Key facts

Severity: Medium (CVSS 3.x base score 4.7)
CVSS v4: 2.3
EPSS exploit prediction: 0% (16th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-942
Published: 2026-06-29
Last modified: 2026-07-01

Description

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.

Frequently asked questions

What is 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.
How severe is CVE-2026-57957?: CVE-2026-57957 has a CVSS 3.x base score of 4.7, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is none, integrity low, and availability none.
Is CVE-2026-57957 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (16th percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2026-57957?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2026-57957 published?: CVE-2026-57957 was published on 2026-06-29 and last updated on 2026-07-01.

References

Other CWE-942 vulnerabilities

CVE-2022-26969 — Critical (CVSS 9.8): In Directus before 9.7.0, the default settings of CORS_ORIGIN and CORS_ENABLED are true.
CVE-2022-31736 — Critical (CVSS 9.8): A malicious website could have learned the size of a cross-origin resource that supported Range requests. This…
CVE-2026-34449 — Critical (CVSS 9.6): SiYuan is a personal knowledge management system. Prior to version 3.6.2, a malicious website can achieve Remote Code…
CVE-2026-30924 — Critical (CVSS 9.6): qui is a web interface for managing qBittorrent instances. Versions 1.14.1 and below use a permissive CORS policy that…
CVE-2026-9739 — Critical (CVSS 9.4): Vulnerable to DNS rebinding attacks when using SSE (http://b/499408790). During the beta phase, we implemented…
CVE-2026-8948 — Critical (CVSS 9.1): Same-origin policy bypass in the DOM: Networking component. This vulnerability was fixed in Firefox 151 and Thunderbird…

Browse all CWE-942 vulnerabilities →