# CVE-2025-56223: Ascertia SigningHub denial of service in UploadStreamDocument

Source: https://junglewise.ai/threats/cve-2025-56223-ascertia-signinghub-denial-of-service-in-uploadstreamdocument  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2025-10-20. Updated: 2026-07-05  
License: CC BY 4.0 with a link back

CVE-2025-56223 · Severity: high · CVSS 7.5 · Published 2025-10-20

SigningHub is a digital signature platform used by organizations to securely sign and manage documents. A vulnerability in the document upload component allows an attacker to repeatedly upload files without restriction. This can lead to a denial-of-service (DoS) condition, making the platform unavailable to legitimate users by exhausting server resources or disk space.

Technologies: [Ascertia Signinghub](https://junglewise.ai/threats/technologies/signinghub). Vendors: [Ascertia](https://junglewise.ai/threats/vendors/ascertia).

## Quick answers

**Is CVE-2025-56223 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2025-56223 being exploited in the wild.

**How severe is CVE-2025-56223?** High severity, with a CVSS score of 7.5, published 20 October 2025.

**Which products and versions are affected?** Ascertia Signinghub <= 8.6.8.

**Is there a fix for CVE-2025-56223?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2025-56223 attacked?** It is attacked over the network, in a network appliance.

**Am I affected by CVE-2025-56223?** Check whether you run Ascertia Signinghub at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

A resource exhaustion vulnerability exists in the SigningHub Upload Document API (/Home/UploadStreamDocument). The component fails to implement rate limiting or throttling on file uploads. A remote attacker can exploit this by rapidly uploading a large volume of files, leading to disk space depletion, high CPU/memory load, and overall service degradation. The vulnerability is confirmed in version 8.6.8 and earlier; remediation involves upgrading to a version later than 8.6.8 or implementing server-side rate limiting.

## Affected products

- Ascertia SigningHub <= 8.6.8

## Timeline

- 2025-10-20: disclosed
- 2025-10-20: advisory

## References

- [http://signinghub.com/](http://signinghub.com/)
- [https://github.com/saykino/CVE-2025-56223](https://github.com/saykino/CVE-2025-56223)

## Related threats

- [An open redirect in Ascertia SigningHub User v10.0 allows attackers to redirect users to a malicious site via a crafted URL.](https://junglewise.ai/threats/cve-2025-61166-an-open-redirect-in-ascertia-signinghub-user-v10-0-allows)
- [In Ascertia SigningHub through 8.6.8, there is a lack of rate limiting on the reset password function, leading to an…](https://junglewise.ai/threats/cve-2025-54321-in-ascertia-signinghub-through-8-6-8-there-is-a-lack-of-rate)
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- [Ascertia SigningHub OTP verification bypass via brute force](https://junglewise.ai/threats/cve-2025-56224-ascertia-signinghub-otp-verification-bypass-via-brute-force)
- [Ascertia SigningHub improper access control in Add User API](https://junglewise.ai/threats/cve-2025-56219-ascertia-signinghub-improper-access-control-in-add-user-api)