Auth bypass in Opensignlabs Opensign

CVE-2026-72545

An insecure direct object reference vulnerability in OpenSignLabs OpenSign through 2.37.0 allows unauthenticated remote attackers to write to any contact record via the updatecontacttour Parse cloud function. The function performs no authentication or authorization before updating the target contact record. An attacker can corrupt or overwrite contact data for any user in the system 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:N/I:H/A:N.

EPSS exploit prediction

EPSS: 0.005 (42.8th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 43rd percentile — 42.8% 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-2026-72545: held from 0.004 to 0.005.

EPSS over last 30 days · oldest: 0.004 · newest: 0.005 · change: +0.001

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-72545?
CVE-2026-72545 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-2026-72545?
High severity. CVSS v3 base score is 7.5 out of 10.