Vanetza: Remote Denial of Service via Uncaught OER Encoding Exception in Cryptographic Verification
riebl · vanetza
Official source article: GitHub GHSA-Q9FQ-3RX9-7XCV ↗. Check the applicable product and release in the original source.
7.5HighCVSS 3.1
Recommended action
Within 7 days
High technical severity with public exploit material referenced by a structured source; prioritise exposed affected systems while verifying vendor guidance.
Published severityHigh→Operational priority:Critical, raised one band.upgradedsince 27 May 2026
Evidence used
No CISA KEV confirmation is currently recorded.
A structured source references public exploit or proof-of-concept material.
The selected CVSS metric records a network-reachable, unauthenticated path with no user interaction.
EPSS is 0.33% for the current model date.
Compensating controls
Restrict the affected network interface to trusted sources where business-safe.
Increase monitoring for the attack path and post-exploitation behaviour described in the report.
Verification
Confirm that the asset runs riebl vanetza and falls inside the recorded affected range.
Recheck the vendor advisory before scheduling a change because no verified fixed version is currently retained.
Validate exposure, authentication requirements and compensating controls in the actual environment.
Reopen this reassessment when CVSS, KEV, EPSS, exploit evidence or remediation changes.
Optional official sources
National CERT insights ?CERT means Computer Emergency Response Team; CSIRT is the closely related term Computer Security Incident Response Team.
Choose official national sources for this report. Each advisory shows its original language. Your selection is remembered on this device and included in shared links.
Official European source
ENISA European Vulnerability Database
Official EUVD identifiers, advisory evidence and known-exploited context. Missing fields are not treated as evidence of low risk.
1 current
ENISA EUVD identifier
EUVD-2026-32006
No EUVD known-exploited evidence
ENISA has published the identifier mapping but no EUVD description has been stored yet.
EUVD state
Present in the current official mapping
Known exploitation
Not present in the current ENISA EUVD known-exploited dataset. This is not proof of no exploitation.
ENISA score
Not supplied in the stored EUVD record
Advisory evidence
No linked advisory details stored yet
Recommended actionWithin 7 days
High technical severity with public exploit material referenced by a structured source; prioritise exposed affected systems while verifying vendor guidance.
Fix not verified
01
What, why and how
Vanetza is an open-source implementation of the ETSI C-ITS protocol suite. In 26.02 and earlier, a denial-of-service vulnerability was identified in the cryptographic verification pipeline of Vanetza. When processing incoming V2X messages, the ASN.1 decoder accepts the structure as syntactically valid. However, this reveals a logic-based protocol failure where semantic constraints on specific fields are only strictly enforced during OER re-encoding. Specifically, if a crafted packet contains a certificate where the Psid (Provider Service Identifier) sub-type violates subtype constraints (e.g., out-of-range or invalid CHOICE variant), it is accepted during initial parsing, where subtype constraints are not enforced. Later, when StraightVerifyService attempts to calculate a message hash for cryptographic verification, it must re-encode the signing certificate. The underlying ASN.1 wrapper (asn1c_wrapper.cpp) detects the semantic violation during encoding and raises a std::runtime_error. This exception is not caught within the encoding path and propagates to std::terminate, resulting in immediate process termination. This vulnerability is fixed with commit e1a2e2709210d309458c3d77f98d50dec26c0df0.
What
Vanetza is an open-source implementation of the ETSI C-ITS protocol suite. In 26.02 and earlier, a denial-of-service vulnerability was identified in the cryptographic verification pipeline of Vanetza. When processing incoming V2X messages, the ASN.1 decoder accepts the structure as syntactically valid. However, this reveals a logic-based protocol failure where semantic constraints on specific fields are only strictly enforced during OER re-encoding. Specifically, if a crafted packet contains a certificate where the Psid (Provider Service Identifier) sub-type violates subtype constraints (e.g., out-of-range or invalid CHOICE variant), it is accepted during initial parsing, where subtype constraints are not enforced. Later, when StraightVerifyService attempts to calculate a message hash for cryptographic verification, it must re-encode the signing certificate. The underlying ASN.1 wrapper (asn1c_wrapper.cpp) detects the semantic violation during encoding and raises a std::runtime_error. This exception is not caught within the encoding path and propagates to std::terminate, resulting in immediate process termination. This vulnerability is fixed with commit e1a2e2709210d309458c3d77f98d50dec26c0df0.
Why
An exception is thrown from a function, but it is not caught.
How
An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.
What
Vanetza is an open-source implementation of the ETSI C-ITS protocol suite. In 26.02 and earlier, a denial-of-service vulnerability was identified in the cryptographic verification pipeline of Vanetza. When processing incoming V2X messages, the ASN.1 decoder accepts the structure as syntactically valid. However, this reveals a logic-based protocol failure where semantic constraints on specific fields are only strictly enforced during OER re-encoding. Specifically, if a crafted packet contains a certificate where the Psid (Provider Service Identifier) sub-type violates subtype constraints (e.g., out-of-range or invalid CHOICE variant), it is accepted during initial parsing, where subtype constraints are not enforced. Later, when StraightVerifyService attempts to calculate a message hash for cryptographic verification, it must re-encode the signing certificate. The underlying ASN.1 wrapper (asn1c_wrapper.cpp) detects the semantic violation during encoding and raises a std::runtime_error. This exception is not caught within the encoding path and propagates to std::terminate, resulting in immediate process termination. This vulnerability is fixed with commit e1a2e2709210d309458c3d77f98d50dec26c0df0.
Why
An exception is thrown from a function, but it is not caught.
How
An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.
02
Exploit reality and attack path
CVSS severity, EPSS forecast probability, public exploit material and CISA-confirmed exploitation are separate signals.
Observed exploitation ?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.No confirmed evidence
No CISA KEV match was present at the last successful refresh. This means no confirmation from that source, not proof of no exploitation.
Public PoC / exploit material ?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.Reference recorded
CISA Vulnrichment records proof-of-concept exploitation in its SSVC data. BlackTree has not independently executed or validated exploit material.
Likely attack path
a network path → Uncaught Exception → cause the confidentiality, integrity or availability impact described by the vendor
Attack surface
Network
Privileges required
None: unauthenticated exploitation is possible
User interaction
None
Attack complexity
Low: no specialised conditions are recorded
Security boundary
Unchanged: impact remains within the vulnerable component's security authority
Weakness ?CWE means Common Weakness Enumeration: a standard category for the underlying weakness.
CWE-248: Uncaught Exception. An exception is thrown from a function, but it is not caught.
CVSS vector ?CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Common Vulnerability Scoring System 3.1: the compact vector below is decoded into plain language.
AVNetworkAttack vector: The vulnerable component can be reached over a network.ACLowAttack complexity: No specialised conditions are required beyond attacker-controlled input.PRNonePrivileges required: The attacker does not need an account or existing privileges.UINoneUser interaction: No action by another user is required.SUnchangedScope: The security impact remains within the vulnerable component's authority.CNoneConfidentiality impact: No direct loss is represented by this metric.INoneIntegrity impact: No direct loss is represented by this metric.AHighAvailability impact: A successful attack can cause a major loss.
Post-exploitation / living off the land
No specific living-off-the-land technique is confirmed in the structured sources. Monitor normal administration tools for activity inconsistent with the affected service's baseline.
Operational remediation based on structured source evidence.
Status ?Patch availability is based on structured fixed-version fields and authoritative update references. If no fix is verified, check the vendor advisory before making a change.
No fixed version is explicitly recorded in the structured CVE data.
Action
No verified patch reference is present in the current structured sources. Check the vendor advisory before making a change.
Workaround
No verified workaround is recorded. If business-safe, reduce exposure to the affected interface and allow only trusted sources until authoritative guidance is available.
04
Evidence and provenance
Published 26 May 2026 · Last source change 27 May 2026, 13:01 UTC · CWE-248 · Uncaught Exception
CVE recordCVE.org · 5.2
CVSS sourceCNA
EPSS source ?The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.FIRST · tracked since 2026-08-14
European sourceENISA EUVD · EUVD-2026-32006
Product sourceCNA
Remediation sourceCVE/CNA references
CWE sourceCNA
NVD statusNVD not scheduled
Core structured fields are present and their contributing authorities are shown above.
Technical terms and abbreviations used in this report
CVE
Common Vulnerabilities and Exposures: the public identifier for one disclosed vulnerability.
CVSS
Common Vulnerability Scoring System: a technical severity framework; it is not patching priority by itself.
EPSS
Exploit Prediction Scoring System: FIRST's estimate of the probability that exploitation activity will be observed in the next 30 days; it is a forecast, not confirmation.
CWE
Common Weakness Enumeration: the standard category describing the underlying software or hardware weakness.
CNA
CVE Numbering Authority: an organisation authorised to assign and publish CVE records.
CISA ADP
Cybersecurity and Infrastructure Security Agency Authorized Data Publisher: structured enrichment added to a CVE record.
NVD
National Vulnerability Database: NIST's enrichment service for CVE records.
CERT / CSIRT
A computer security incident response team that publishes warnings or coordinates incident response.
PoC
Proof of concept: public material that demonstrates or helps reproduce exploitation.
CSAF
Common Security Advisory Framework: a machine-readable format for security advisories.
LoTL
Living off the land: abuse of legitimate tools or system functions during an attack.