Invalid-signature acceptance via uncaught validation exceptions
Published Aug 10, 2026 · Updated Aug 10, 2026
Signature verification flaws in RIA libdigidocpp and DigiDoc applications allow attackers to make invalid digital signatures appear valid. SignatureXAdES validation previously let processing exceptions bypass the accumulated validation-error path instead of recording a failed signature check. Exploitation requires a user or integrating application to validate a specially structured signed document, after which altered content can be trusted as authentically signed.
Summary
What happened
Signature verification flaws in RIA libdigidocpp and DigiDoc applications allow attackers to make invalid digital signatures appear valid. SignatureXAdES validation previously let processing exceptions bypass the accumulated validation-error path instead of recording a failed signature check. Exploitation requires a user or integrating application to validate a specially structured signed document, after which altered content can be trusted as authentically signed.
The record
- CVE
- CVE-2026-59112
- Published
- Aug 10, 2026
- Updated
- Aug 10, 2026
- Vendor
- Estonian Information System Authority
- Product
- libdigidocpp
- Classifications
- CWE-347, CWE-754
- Attack vector
- local
- Privileges
- unauthenticated
Timeline
How it unfolded
- Aug 10, 2026CVE publishedPublication date reported by the CVE source.
- Aug 10, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=4.1.0 <4.2.1
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- libdigidocpp pull request 690 validation reproducerproof of concept · unverified
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Technologies
Your stack
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Your stack
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