# CVE-2026-103902: DigiDoc improper signature verification

> Attackers can forge digital signatures that appear valid in DigiDoc applications, compromising document integrity and trust.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 12 Oct 2026
- **Updated:** 15 Oct 2026
- **Also known as:** GHSA-jjqw-f3cg-gjjw, UBUNTU-CVE-2026-103902

## What is CVE-2026-103902?

CVE-2026-103902 is a high-severity vulnerability in DigiDoc Android, published on 12 Oct 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official 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.

Weakness: CWE-347 (Improper Verification of Cryptographic Signature)

## Which versions are affected by CVE-2026-103902?


## How do I fix CVE-2026-103902?

No fix has been published for CVE-2026-103902 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-103902 being exploited?

There is no known exploitation of CVE-2026-103902 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-103902 and fix it if it is affected.

What it is: CVE-2026-103902 is a high-severity vulnerability in DigiDoc Android, published on 12 Oct 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-103902 in the wild and no public exploit code.

Affected product: DigiDoc Android. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-103902/ (Markdown: https://insights.sbomify.com/CVE-2026-103902/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-103902
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-103902
- OSV: https://osv.dev/vulnerability/CVE-2026-103902

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-103902/
Summaries are generated and may contain mistakes; the official description above is the record.