Vulnerability-Lookup

GHSA-FPP4-5G35-6QQ3

Vulnerability from github – Published: 2026-11-06 18:35 – Updated: 2026-11-06 18:35

Details

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.

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JSON

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{
  "affected": [],
  "aliases": [
    "CVE-2026-12067"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-248"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-11-06T16:17:55Z",
    "severity": null
  },
  "details": "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.\n\n\n\nThe vulnerability spans multiple handler pathways in the RPC-based native message protocol:\n\n  *  Log_NmSvc.message handler: converts JSON fields to strings without type validation and without exception boundaries.\u00a0\n  *  OpenInSz_NmSvc handler: converts URL and origin fields to strings without type checking, exposing an exception.\n  *  OpenInSz_NmSvc.profile handler: converts the profile field to an integer without validation.\n\n\nIn all three cases, the exceptions are not caught by action-specific handlers and propagate up the dispatcher.\u00a0The common root cause is the absence of try-catch blocks around JSON type conversions in the native message processing chain.",
  "id": "GHSA-fpp4-5g35-6qq3",
  "modified": "2026-11-06T18:35:14Z",
  "published": "2026-11-06T18:35:13Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-12067"
    },
    {
      "type": "WEB",
      "url": "https://support.avast.com/en-us/article/Update-Antivirus"
    },
    {
      "type": "WEB",
      "url": "https://support.avg.com/SupportArticleView?l=en\u0026urlname=Update-AVG-Antivirus"
    },
    {
      "type": "WEB",
      "url": "https://support.norton.com/sp/en/us/home/current/solutions/v20240108175512167"
    },
    {
      "type": "WEB",
      "url": "https://www.gendigital.com/us/en/contact-us/security-advisories"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}

CVE-2026-12067 (GCVE-0-2026-12067)

Vulnerability from cvelistv5 – Published: 2026-11-06 15:57 – Updated: 2026-11-06 15:57

Title

AvastSvc denial of service via unhandled JsonCpp exceptions in native message handlers

Summary

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.

Severity

No CVSS data available.

CWE

CWE-248 - Uncaught Exception
CWE-391 - Unchecked Error Condition

Assigner

GEN CNA under the mitre root

CNA scorecard B 75/100 over 24 records in the last 180 days details

References

4 references

URL	Tags
https://www.gendigital.com/us/en/contact-us/secur…	vendor-advisory
https://support.avast.com/en-us/article/Update-An…	patch
https://support.avg.com/SupportArticleView?l=en&u…	patch
https://support.norton.com/sp/en/us/home/current/…	patch

Impacted products

3 products

Vendor	Product	Version
Gen Digital	Avast Antivirus, Avast One, Avast Premium Security, Avast Ultimate, Avast Business Security	Affected: 0 , < 26.7 (custom)
Gen Digital	AVG Antivirus Free, AVG Internet Security, AVG Ultimate	Affected: 0 , < 26.7 (custom)
Gen Digital	Norton Antivirus Plus, Norton 360 Standard, Norton 360 Deluxe, Norton 360 Advanced	Affected: 0 , < 26.7 (custom)

Credits

Teng Zheng Wang by VulnGuard Labs

Show details on NVD website

JSON

To clipboard

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      "affected": [
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          "defaultStatus": "affected",
          "platforms": [
            "Windows"
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          "product": "Avast Antivirus, Avast One, Avast Premium Security, Avast Ultimate, Avast Business Security",
          "vendor": "Gen Digital",
          "versions": [
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              "value": "\u003cp\u003eMissing exception handlers in AvastSvc native message dispatcher (\u003ccode\u003eashServ.dll\u003c/code\u003e) on Windows allow a local, unprivileged attacker to crash the service by sending specially crafted JSON messages.\u003c/p\u003e\u003cp\u003eThe vulnerability spans multiple handler pathways in the RPC-based native message protocol:\u003c/p\u003e\u003col\u003e\u003cli\u003e\u003cstrong\u003eLog_NmSvc.message handler:\u003c/strong\u003e converts JSON fields to strings without type validation and without exception boundaries.\u0026nbsp;\u003c/li\u003e\u003cli\u003e\u003cstrong\u003eOpenInSz_NmSvc handler:\u003c/strong\u003e converts URL and origin fields to strings without type checking, exposing an exception.\u003c/li\u003e\u003cli\u003e\u003cstrong\u003eOpenInSz_NmSvc.profile handler:\u003c/strong\u003e converts the profile field to an integer without validation.\u003c/li\u003e\u003c/ol\u003e\u003cp\u003eIn all three cases, the exceptions are not caught by action-specific handlers and propagate up the dispatcher.\u0026nbsp;The common root cause is the absence of try-catch blocks around JSON type conversions in the native message processing chain.\u003c/p\u003e"
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Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Vulnerability timeline

Sightings and recorded dates, grouped by day · UTC

Order JSON

How durations are calculated

Following the VTEM framework (Black Hat USA 2015), time to patch starts when the vendor or a coordinator was informed, total time to patch at discovery, and disclosure to patch at public disclosure; vendor response time runs from the report to its acknowledgement. Time to exploit and time unpatched start at the earliest discovery or report, falling back to public disclosure. Unpatched time ends at the first recorded patch, or the calculation time when no patch is recorded. Exploitation to patch shows the interval between those two events; a published proof of concept is a public exploit, not exploitation.

Each result shows its source dates. A negative interval means the end event came first; when date-only inputs leave the order open, the result says so. Date-only inputs are approximate. The earliest evidence wins: KEV report dates and sightings are labelled as such. Records describing another vulnerability are listed but never calculated from, and a PoC alone does not establish exploitation. Missing patch evidence does not prove that no patch exists. Filters below change the event list only.

Publication & reservation Sightings KEV catalogs Other timestamps

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The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.

Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.

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