CVE-2026-12067
AvastSvc denial of service via unhandled JsonCpp exceptions in native message handlers
No known exploitation. EPSS puts it in the 24th percentile. Fixed in 26.7.
No public exploit knownFix26.7Upgrade to this build
No ready-made check. Neither Nuclei nor OpenVAS has one for this CVE yet.
What to do
Find your product and version, then upgrade to the build on the right.
- Gen Digital Avast Antivirus, Avast One, Avast Premium Security, Avast Ultimate, Avast Business SecurityAffected: < 26.7Upgrade to: 26.7Stated by: CVE record
- Gen Digital AVG Antivirus Free, AVG Internet Security, AVG UltimateAffected: < 26.7Upgrade to: 26.7Stated by: CVE record
- Gen Digital Norton Antivirus Plus, Norton 360 Standard, Norton 360 Deluxe, Norton 360 AdvancedAffected: < 26.7Upgrade to: 26.7Stated by: CVE record
Versions as the sources state them. Full version matrix after sign-in
What it is
From the CVE record
Missing exception handlers in AvastSvc native message dispatcher (ashServ.dll) on Windows allow a local, unprivileged attacker to crash the service by sending specially crafted JSON messages. The vulnerability spans multiple handler pathways in the RPC-based native message protocol: * Log_NmSvc.message handler: converts JSON fields to strings without type validation and without exception boundaries. * OpenInSz_NmSvc handler: converts URL and origin fields to strings without type checking, exposing an exception. * OpenInSz_NmSvc.profile handler: converts the profile field to an integer without validation. In all three cases, the exceptions are not caught by action-specific handlers and propagate up the dispatcher. The common root cause is the absence of try-catch blocks around JSON type conversions in the native message processing chain.
In plain language
No plain-language summary for this CVE yet.
Exploitation
Where each signal puts this CVE on the scale from published to confirmed exploited.
- CISA KEV
Not in the catalog. CISA has not confirmed exploitation.
- Public exploits
No public exploit or proof of concept found in the sources we track.
- EPSS
0.3% chance of exploitation activity in the next 30 days, which ranks it in the 24th percentile of scored CVEs.
Exploit Prediction Scoring System, FIRST.org. A probability, not a confirmation.
Lifecycle
7 events over 4 days, from the signal feeds we watch.
- Patch availablerecord updated
- Patch availablepatch available, published, weakness classified, record updated
Affected products
- Avast Antivirus, Avast One, Avast Premium Security, Avast Ultimate, Avast Business SecuritySecurity Products / endpoint-av-edr
- AVG Antivirus Free, AVG Internet Security, AVG UltimateSecurity Products / endpoint-av-edr
- Norton Antivirus Plus, Norton 360 Standard, Norton 360 Deluxe, Norton 360 AdvancedSecurity Products / endpoint-av-edr
Technical detail
CVSS 3.1 vector
Open in the CVSS calculatorCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Scored 6.5 by NVD.
How it is reached
- Attack Vector NetworkExploitable remotely over the network without any special conditions
- Attack Complexity LowNo special conditions — the attack can be reliably reproduced
- Privileges Required LowRequires basic user-level privileges
- User Interaction NoneNo user interaction needed — fully automated exploitation
Scope
- Scope UnchangedImpact is limited to the vulnerable component itself
Impact if exploited
- Confidentiality NoneNo confidentiality impact
- Integrity NoneNo integrity impact
- Availability HighTotal denial of service — the component is completely unavailable
Weaknesses
Sources
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