CVE-2026-48509
Insecure Default Initialization: is CVE-2026-48509real, exploitable, or a false positive? Here's the community verdict.
signals
public sources
High CVSS base score, but low real-world exploitation probability (EPSS). Likely less urgent than the score implies.
baseline read
auto · not a community verdict
Real, but low real-world risk
A genuine vulnerability on paper, but EPSS shows little real-world exploitation — the base score may overstate urgency. This is not the same as a false positive.
Based on CVSS · FIRST EPSS
Confirm or dispute →CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H
MessagePack for C# is a MessagePack serializer for C#. Prior to 2.5.301 and 3.1.7, the parameterless MessagePackInputFormatter() constructor uses default serializer options, which resolve to MessagePackSerializerOptions.Standard with MessagePackSecurity.TrustedData. The formatter is designed for ASP.NET Core MVC request bodies, which commonly cross an HTTP trust boundary. This insecure default can expose applications to denial-of-service attacks that MessagePackSecurity.UntrustedData is intended to mitigate, such as hash-collision attacks against dictionary-like model properties. This vulnerability is fixed in 2.5.301 and 3.1.7.
References
Published
Embed this verdict
[](https://www.truepositive.app/cve/CVE-2026-48509)<a href="https://www.truepositive.app/cve/CVE-2026-48509"><img src="https://www.truepositive.app/cve/CVE-2026-48509/badge.svg" alt="TruePositive verdict for CVE-2026-48509"></a>Live badge that updates automatically as the community verdict changes.
Community ground truth
Be the first practitioner to weigh in
So far this is only TruePositive's editorial baseline from public sources. Add your real-world verdict below — it becomes the signal the next person triaging this relies on.
🥇 The first 50 practitioners to contribute earn a Founding Contributor badge.
In your experience, is this finding real and exploitable?
0 verdictsNo account needed. Anonymous verdicts post as an unverified signal. Log in to make yours verified and earn reputation.
Field notes & remediation
Verdicts are the quick signal. Notes are the evidence and fixes behind them.
No notes yet. Be the first to share what you saw, or a fix that worked.
Add a field note or remediationoptional
Related CVEs
Same weakness: CWE-1188 · Insecure Default Initialization.
- CVE-2023-27524HIGH 8.9KEVEPSS 97%
Session Validation attacks in Apache Superset versions up to and including 2.0.1. Installations that have not altered the default configured SECRET_KEY according to installation instructions allow for an attacker to authenticate and access unauthorized resources. This does not affect Superset administrators who have changed the default value for SECRET_KEY config. All superset installations should always set a unique secure random SECRET_KEY. Your SECRET_KEY is used to securely sign all session cookies and encrypting sensitive information on the database. Add a strong SECRET_KEY to your `superset_config.py` file like: SECRET_KEY = <YOUR_OWN_RANDOM_GENERATED_SECRET_KEY> Alternatively you can set it with `SUPERSET_SECRET_KEY` environment variable.
- CVE-2022-24706CRIT 9.8KEVEPSS 92%
In Apache CouchDB prior to 3.2.2, an attacker can access an improperly secured default installation without authenticating and gain admin privileges. The CouchDB documentation has always made recommendations for properly securing an installation, including recommending using a firewall in front of all CouchDB installations.
- CVE-2026-50519MED 6.5EPSS 1%
Initialization of a resource with an insecure default in GitHub Copilot and Visual Studio Code allows an unauthorized attacker to disclose information over a network.
- CVE-2026-40994HIGH 8.2Real · low riskEPSS 0%
Wss4jSecurityInterceptor initialized its BSP (WS-I Basic Security Profile) compliance flag so that inbound validation disabled WSS4J BSP enforcement on RequestData. Services that validate WS-Security on the network could therefore accept messages that violate BSP rules, weakening protocol-level checks. Affected versions: Spring Web Services 5.0.0 through 5.0.1; 4.1.0 through 4.1.3; 4.0.0 through 4.0.18; 3.1.0 through 3.1.8.