CVE-2026-72543Network attack vector

Unauthenticated contact disclosure via privileged object lookup

Published Aug 11, 2026 · Updated Aug 11, 2026

IDOR in OpenSignLabs OpenSign through 2.37.0 allows unauthenticated remote attackers to read contact records via the getcontact cloud function. The function runs its caller-supplied object lookup with useMasterKey and returns the selected object without authentication or an ownership check. Any network client that can reach the Parse endpoint can enumerate contact identifiers and disclose all stored contact records, including personally identifiable information.

CVSS severity7.5
High
EPSS probability0.45%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

IDOR in OpenSignLabs OpenSign through 2.37.0 allows unauthenticated remote attackers to read contact records via the getcontact cloud function. The function runs its caller-supplied object lookup with useMasterKey and returns the selected object without authentication or an ownership check. Any network client that can reach the Parse endpoint can enumerate contact identifiers and disclose all stored contact records, including personally identifiable information.

The record

CVE
CVE-2026-72543
Published
Aug 11, 2026
Updated
Aug 11, 2026
Vendor
OpenSignLabs
Product
OpenSign
Classifications
CWE-639, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 11, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 11, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <=2.37.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

OpenSignLabs · OpenSignversion=0 <=2.37.0

Published CVSS scores

7.5TuranSecCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-639Authorization Bypass Through User-Controlled Key
T1190Exploit Public-Facing Application

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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