CVE-2026-72691Network attack vectorHinoki check available

Unauthenticated file access via docId authentication bypass

Published Aug 10, 2026 · Updated Aug 10, 2026

Authentication bypass in OpenSignLabs OpenSignServer through 2.37.0 allows remote attackers to mint signed tokens for stored files. The getsignedurl Parse cloud function omits isAuthenticated whenever any docId value is present, including a nonexistent identifier. Network access to the cloud-function endpoint is sufficient; a crafted request yields MASTER_KEY-signed access to arbitrary stored files without a session.

CVSS severity7.5
High
EPSS probability0.39%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkAvailable
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Summary

What happened

Authentication bypass in OpenSignLabs OpenSignServer through 2.37.0 allows remote attackers to mint signed tokens for stored files. The getsignedurl Parse cloud function omits isAuthenticated whenever any docId value is present, including a nonexistent identifier. Network access to the cloud-function endpoint is sufficient; a crafted request yields MASTER_KEY-signed access to arbitrary stored files without a session.

The record

CVE
CVE-2026-72691
Published
Aug 10, 2026
Updated
Aug 10, 2026
Vendor
OpenSignLabs
Product
OpenSignServer
Classifications
CWE-288, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 10, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 10, 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 · OpenSignServerversion=0 <=2.37.0

Published CVSS scores

7.5CVE CNA recordCVSS: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.

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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-288Authentication Bypass Using an Alternate Path or Channel
T1190Exploit Public-Facing Application

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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