OpenSignLabs OpenSignServer up to 2.37.0 getsignedurl docId improper authentication

Summaryinfo

A vulnerability, which was classified as problematic, was found in OpenSignLabs OpenSignServer up to 2.37.0. Affected by this vulnerability is the function getsignedurl. The manipulation of the argument docId results in improper authentication. This vulnerability is identified as CVE-2026-72691. The attack can be executed remotely. There is not any exploit available.

Detailsinfo

A vulnerability was found in OpenSignLabs OpenSignServer up to 2.37.0. It has been classified as problematic. Affected is the function getsignedurl. The manipulation of the argument docId with an unknown input leads to a improper authentication vulnerability. CWE is classifying the issue as CWE-287. When an actor claims to have a given identity, the product does not prove or insufficiently proves that the claim is correct. This is going to have an impact on confidentiality. CVE summarizes:

An authentication bypass vulnerability in OpenSignLabs opensignserver through 2.37.0 allows an unauthenticated remote attacker to mint MASTER_KEY-signed file access tokens for arbitrary stored files via the getsignedurl Parse cloud function. The function skips its isAuthenticated check whenever any docId parameter is supplied, even one corresponding to no real document, allowing the authentication gate to be bypassed by supplying an arbitrary string as docId.

The advisory is shared for download at github.com. This vulnerability is traded as CVE-2026-72691 since 08/10/2026. The exploitability is told to be easy. It is possible to launch the attack remotely. The exploitation doesn't require any form of authentication. There are known technical details, but no exploit is available. The current price for an exploit might be approx. USD $0-$5k (estimation calculated on 08/10/2026).

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

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Productinfo

Vendor

• OpenSignLabs

Name

• OpenSignServer

Version

• 2.0
• 2.1
• 2.2
• 2.3
• 2.4
• 2.5
• 2.6
• 2.7
• 2.8
• 2.9
• 2.10
• 2.11
• 2.12
• 2.13
• 2.14
• 2.15
• 2.16
• 2.17
• 2.18
• 2.19
• 2.20
• 2.21
• 2.22
• 2.23
• 2.24
• 2.25
• 2.26
• 2.27
• 2.28
• 2.29
• 2.30
• 2.31
• 2.32
• 2.33
• 2.34
• 2.35
• 2.36
• 2.37.0

CPE 2.3info

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CPE 2.2info

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