libdigidocpp: Improper Verification of Cryptographic Signature
CVE-2026-103902 is a high-severity improper verification of cryptographic signature vulnerability in libdigidocpp from DigiDoc, with a CVSS 3.1 base score of 7.5 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. The record lists version 4.5.0 as the first without the flaw, so updating libdigidocpp to that release or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.15% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update libdigidocpp to 4.5.0 or a later version.
- Update DigiDoc4 to 4.11.0 or a later version.
- Update DigiDoc Android to 3.1.0 or a later version.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| DigiDoc | libdigidocpp | 4.0.0 up to, but not including, 4.5.0 | 4.5.0 |
| DigiDoc | DigiDoc4 | 4.6.0 up to, but not including, 4.11.0 | 4.11.0 |
| DigiDoc | DigiDoc Android | 2.7.0 up to, but not including, 3.1.0 | 3.1.0 |
| DigiDoc | DigiDoc iOS | 2.7.0 up to, but not including, 3.1.0 | 3.1.0 |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- NoneNo data is disclosed.
- Integrity
- HighData or code can be modified at will.
- Availability
- NoneAvailability is not affected.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N. Scored by CNA.
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.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Verification of Cryptographic Signature
The product does not verify, or incorrectly verifies, the cryptographic signature for data.
More Improper Verification of Cryptographic Signature vulnerabilities (CWE-347)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
Other references
Recent Improper Verification of Cryptographic Signature vulnerabilities
- 7.3 High severity
- 9.8 Critical severity
- 9.8 Critical severity
- 7.4 High severity
- 9.8 Critical severity
- 7.8 High severity
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