Auth bypass in Opensignlabs Opensign

CVE-2026-72543

An insecure direct object reference vulnerability in OpenSignLabs OpenSign through 2.37.0 allows unauthenticated remote attackers to retrieve any contact record via the getcontact Parse cloud function. The function executes with useMasterKey and performs no authentication or authorization checks before returning the requested contact object. An attacker can enumerate and read all contact records including personally identifiable information without credentials.

Vulnerability class: IDOR (Insecure Direct Object Reference)

Published · last modified .

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N.

EPSS exploit prediction

EPSS: 0.006 (47.0th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 47th percentile — 47.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2026-72543: held from 0.005 to 0.006.

EPSS over last 30 days · oldest: 0.005 · newest: 0.006 · change: +0.002

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-72543?
CVE-2026-72543 is a high-severity vulnerability in Opensignlabs Opensign, classified under Authorization Bypass Through User-Controlled Key. CVSS score: 7.5/10. Published 2026-08-11.
How severe is CVE-2026-72543?
High severity. CVSS v3 base score is 7.5 out of 10.