CVE-2026-45498
Microsoft Defender Denial of Service Vulnerability
CVSS
4.0
Medium
EPSS
63.1%
p99
KEV
YES
May 20, 2026
Exploit Today
80
0-100
Published: May 20, 2026 · Last modified: Jul 23, 2026 · CWE-400
63.1%EPSS · 30 days63.1%
2026-08-022026-08-31
Product
Microsoft / Defender
Vulnerability
Microsoft Defender Denial of Service Vulnerability
Added to KEV
May 20, 2026
Remediate by
Jun 3, 2026
Known ransomware use
No
Summary description
Microsoft Defender contains an unspecified vulnerability that allows for denial of service.
Required action
Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
Notes
https://msrc.microsoft.com/update-guide/en-US/vulnerability/CVE-2026-45498 ; https://nvd.nist.gov/vuln/detail/CVE-2026-45498
Microsoft Defender Denial of Service Vulnerability
CVECVSSEPSSKEVRExploitTitleMod.
CVE-2026-55520—29.8%
——9Protego is a pure-Python robots.txt parser with support for modern conventions. Prior to 0.6.2, protego._urlpattern._URLPattern._prepare_pattern_for_regex translates every asterisk in an Allow or Disallow directive into a lazy regular-expression wildcard, so a directive containing many asterisks creates exponential backtracking. After protego.Protego.parse processes a crafted robots.txt file, protego.Protego.can_fetch can spend an attacker-controlled period matching a near-miss URL and deny service to the crawler. The vulnerable path is src/protego/_urlpattern.py in the _URLPattern match logic. This issue is fixed in version 0.6.2.3dCVE-2026-552489.1 CRI24.3%
——7plone.app.portlets provides portlets and a Plone-specific user interface for plone.portlets. Prior to 5.0.8, 6.0.4, and 7.0.2, a member who can add an RSS portlet can set its feed URL to a very large response, causing src/plone/app/portlets/portlets/rss.py to download and retain excessive data in memory and deny service. The same RSS URL handling accepts internal hosts, IP addresses, single-word domains, and explicit ports, allowing server-side requests that can probe internal network services and open ports. A malicious feed item can also supply a JavaScript URL that is retained as the item link and can execute script when used by a victim. The affected logic includes _rss_feed_url_validator, _normal_url_validator, RSSFeed._retrieveFeed, RSSFeed._buildItemDict, and the FEED_DATA in-memory cache. This issue is fixed in versions 5.0.8, 6.0.4, and 7.0.2.3dCVE-2026-552479.1 CRI27.0%
——8plone.app.event provides the event content type for Plone. Prior to versions 5.2.4 and 6.0.1, the iCalendar import in src/plone/app/event/ical/importer.py accepts insufficiently restricted calendar and event URLs, does not adequately bound downloaded bytes or imported events, and commits work per event. A logged-in editor can make the server request internal network resources or local calendar files, exhaust resources and take the site offline, and store a malicious event URL that executes script in another user's browser. The fix restricts accepted URLs, applies MAXIMUM_ICAL_IMPORT_SIZE_BYTES and MAXIMUM_ICAL_IMPORT_EVENTS limits, uses transaction savepoints, and validates event URLs. This issue is fixed in versions 5.2.4 and 6.0.1.3dCVE-2026-551088.5 HIG44.7%
——13KubeVela is an open source application delivery platform. Prior to 1.9.14, from 1.10.0-alpha.1 until 1.10.9, and from 1.11.0-alpha.1 until 1.11.0-alpha.4, the Terraform remote configuration loader in pkg/controller/utils/capability.go, GetTerraformConfigurationFromRemote, clones a repository supplied through a core.oam.dev/v1beta1 ComponentDefinition and follows repository-controlled variables.tf or main.tf symlinks. A user with permission to create or update ComponentDefinition objects can point variables.tf to /dev/zero through terraform.path, after which os.Stat and os.ReadFile follow the link and read an unbounded stream before ParseTerraformVariables or HCL parsing can reject the content. The read can exhaust memory, OOM-kill the cluster-wide vela-core controller, cause repeated Pod restarts, and pressure node memory when no effective container limit is configured. This issue is fixed in versions 1.9.14, 1.10.9, and 1.11.0-alpha.4.3dCVE-2026-386387.5 HIG37.2%
——11An issue in the with_argv function (/unistd/mod.rs) of relibc commit 61f42d allows attackers to cause a Denial of Service (DoS) via a crafted input.3dCVE-2026-386367.5 HIG37.2%
——11An issue in the seekdir() function (/dirent/mod.rs) of relibc commit 61f42d allows attackers to cause a Denial of Service (DoS) via a crafted input.3d