USN-8553-1: .NET vulnerabilities
Artur Stetsko discovered that the .NET did not properly validate authentication data. An attacker could possibly use this issue to elevate privileges. (CVE-2026-47300) Levi Broderick discovered that .NET did not properly handle XML encryption during parsing. An attacker could possibly use this issue to consume excessive resources, resulting in a denial of service. (CVE-2026-47302) Pham Quang Minh discovered that .NET did not properly parse authentication data. An attacker could possibly use this issue to bypass authentication and elevate privileges. (CVE-2026-47303) Levi Broderick discovered that .NET did not properly verify cryptographic signatures during XML encryption. An attacker could possibly use this issue to bypass security features over a network and access encrypted data. (CVE-2026-47304) It was discovered that .NET did not properly validate input during TLS handshakes. An attacker could possibly use this issue to cause .NET to crash, resulting in a denial of service. (CVE-2026-50524) Levi Broderick discovered that .NET did not properly handle resource allocation during XML encryption. An attacker could possibly use this issue to consume excessive resources, resulting in a denial of service. (CVE-2026-50525) Siwei Li discovered that .NET did not properly handle link resolution before file access during the container image build process. A local attacker could possibly use this issue to inject resources that could be incorporated into container images built by other users on the same machine. (CVE-2026-50526) Levi Broderick discovered that .NET did not properly handle memory while performing XML encryption. An attacker could possibly use this issue to cause .NET to crash, resulting in a denial of service. (CVE-2026-50527) Henrique Pereira discovered that .NET did not properly handle authorization checks during TLS/SSL connections. An attacker could possibly use this issue to bypass authorization checks during secure communications. (CVE-2026-50528) It was d
CSIRTS triage
- What
- Multiple vulnerabilities in .NET could allow privilege escalation, denial of service, authentication bypass, and information disclosure.
- Who is affected
- Users of .NET are affected, particularly those using vulnerable features.
- Urgency
- Remediation is critical as these vulnerabilities could be exploited, though exploitation status is not confirmed.
- Action
- Update .NET to the latest version.
AI-assisted analysis generated from the source advisory — verify against the original.
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Details
Original advisory: https://ubuntu.com/security/notices/USN-8553-1
Exploitation outlook
EPSS (FIRST.org) estimates each CVE’s probability of exploitation in the next 30 days — here is the CSIRTS.com read on those numbers.
- Low exploitation riskCVE-2026-473000.53% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 42% of all scored CVEs.
- Moderate exploitation riskCVE-2026-473021.0% 30-day exploitation probability. Patch within normal cadence, watch for KEV listing. Riskier than 60% of all scored CVEs.
- Low exploitation riskCVE-2026-473030.74% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 51% of all scored CVEs.
- Low exploitation riskCVE-2026-473040.22% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 12% of all scored CVEs.
- Low exploitation riskCVE-2026-505240.63% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 47% of all scored CVEs.
- Low exploitation riskCVE-2026-505250.60% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 46% of all scored CVEs.
- Low exploitation riskCVE-2026-505260.24% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 15% of all scored CVEs.
- Low exploitation riskCVE-2026-505270.84% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 54% of all scored CVEs.
- Low exploitation riskCVE-2026-505280.55% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 43% of all scored CVEs.
- Low exploitation riskCVE-2026-506480.84% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 54% of all scored CVEs.
Referenced CVEs
| CVE | CSIRTS overview | External |
|---|---|---|
| CVE-2026-47300 | coverage & exploitation status | NVD · CVE.org |
| CVE-2026-47302 | coverage & exploitation status | NVD · CVE.org |
| CVE-2026-47303 | coverage & exploitation status | NVD · CVE.org |
| CVE-2026-47304 | coverage & exploitation status | NVD · CVE.org |
| CVE-2026-50524 | coverage & exploitation status | NVD · CVE.org |
| CVE-2026-50525 | coverage & exploitation status | NVD · CVE.org |
| CVE-2026-50526 | coverage & exploitation status | NVD · CVE.org |
| CVE-2026-50527 | coverage & exploitation status | NVD · CVE.org |
| CVE-2026-50528 | coverage & exploitation status | NVD · CVE.org |
| CVE-2026-50648 | coverage & exploitation status | NVD · CVE.org |
| CVE-2026-50651 | coverage & exploitation status | NVD · CVE.org |
| CVE-2026-50659 | coverage & exploitation status | NVD · CVE.org |
| CVE-2026-57108 | coverage & exploitation status | NVD · CVE.org |
Same CVEs, other sources
How other CERTs, PSIRTs and databases cover the vulnerabilities in this advisory.
- high[NEW] [high] Microsoft DeveloperTools: Multiple vulnerabilitiescert-bund
- highGHSA-55jh-fwmh-39m4: Microsoft Security Advisory CVE-2026-50526 – .NET Tampering Vulnerabilityghsa
- highGHSA-8prm-248r-h957: Microsoft Security Advisory CVE-2026-47300 – .NET Elevation of Privilege Vulnerabilityghsa
- highGHSA-2p3q-h3hg-jcqq: Microsoft Security Advisory CVE-2026-47303 – .NET Elevation of Privilege Vulnerabilityghsa
- highGHSA-mmjf-rqrv-855v: Microsoft Security Advisory CVE-2026-50527 – .NET Denial of Service Vulnerabilityghsa
- highGHSA-wp74-jgxh-gv4q: Microsoft Security Advisory CVE-2026-50651 – .NET Denial of Service Vulnerabilityghsa
- mediumGHSA-74jp-vm22-8q8x: Microsoft Security Advisory CVE-2026-50659 – .NET Spoofing Vulnerabilityghsa
- highGHSA-8q5v-6pqq-x66h: Microsoft Security Advisory CVE-2026-50525 – .NET Denial of Service Vulnerabilityghsa
- highGHSA-qvw7-jm5c-6hqw: Microsoft Security Advisory CVE-2026-50528 – .NET Security Feature Bypass Vulnerabilityghsa
- highGHSA-23rf-6693-g89p: Microsoft Security Advisory CVE-2026-50648 – .NET Denial of Service Vulnerabilityghsa
- highGHSA-w7cw-xp7h-6j5j: Microsoft Security Advisory CVE-2026-50524 – .NET Denial of Service Vulnerabilityghsa
- highGHSA-g8r8-53c2-pm3f: Microsoft Security Advisory CVE-2026-47304 – .NET Security Feature Bypass Vulnerabilityghsa
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