GCD AI RADAR
incidents/AIR-2026-1293

CVE-2026-53965: MCP PHP SDK unbounded memory buffer vulnerability

Attack on AI2 Disclosed vulnerabilityInfrastructure vulnerability

The Model Context Protocol PHP SDK has an unbounded memory buffer vulnerability in its HTTP client transport during SSE stream processing. A malicious server can cause unlimited memory growth leading to a denial of service.

disclosed CVENo confirmed exploitation, so this record is tracked as a disclosed vulnerability and not counted as an incident. It moves into the counts if CISA or the vendor confirms exploitation. Why

Details

type
Attack on AI
An AI model, agent or AI-powered product was the thing exploited, abused or leaked.
categories
  • Infrastructure vulnerability
    CVEs and advisories in AI frameworks, inference servers, MCP servers, AI developer tools and hosting stacks.
owasp llm top 10
mitre atlas
no technique for these categories
Both rows are derived from the type and categories (OWASP 2025 edition, ATLAS release 2026.09), not classified per record. How
severity
2 · Disclosed vulnerability
CVE or vendor advisory, patched or patchable, no confirmed exploitation.
targets
Framework / tooling
products
MCP PHP SDK
incident date
25 Aug 2026
first reported
25 Aug 2026
origin
NVD
Vulnerability record from NVD / the GitHub Advisory Database. This product uses the NVD API but is not endorsed or certified by the NVD.
classifier confidence
0.95 · published at or above 0.80; see the methodology
tags
CVE-2026-53965 · mcp · infra_vuln
record
created 2026-10-18 10:04Z · updated 2026-10-18 10:04Z · json

Sources · 1

  1. 2026-08-25
    CVE-2026-53965: The MCP PHP SDK (Composer package mcp/sdk) is the official Model Context Protocol SDK for PHP.
    NVD · nvd.nist.gov/vuln/detail/CVE-2026-53965

Titles and links belong to their publishers. The summary above is written by GCD AI RADAR in its own words; data is CC BY-SA 4.0.

Related incidents