Fleet: Unbounded recursion in Apple MDM enrollment plist parsing (DoS)
Summary
Fleet before 4.89.0 contains an unbounded recursion flaw in the parser for Apple MDM enrollment property lists. An unauthenticated attacker with network access to a Fleet server with Apple MDM enabled can send a crafted binary plist of about 150 bytes to the enrollment endpoints. This causes exponential allocation or infinite recursion that exhausts CPU and memory and crashes the server, which disrupts management for the whole instance.
Affected
- Fleet before 4.89.0 (Go package github.com/fleetdm/fleet)
- Only instances with Apple MDM enabled are affected.
Fixed in
- 4.89.0 is the first unaffected version according to the CNA data.
- 4.92.0 moves the protection into the upstream micromdm/plist parser (v0.3.0). Use a current release.
Workaround
- Restrict network access to /api/mdm/apple/enroll and /api/mdm/apple/account_driven_enroll to trusted networks.
- Request size limits do not mitigate this issue because the malicious payload is small.
Exploitation
- CISA SSVC: exploitation none, automatable yes, technical impact partial.
- No known exploitation and no CISA KEV entry in the sources reviewed.
- Public proof-of-concept status is conflicting and unverified.
Our recommendation
- Check whether you run a self-hosted Fleet server with Apple MDM enabled and a version older than 4.89.0.
- Upgrade to a current Fleet release (4.92.0 or later) as a priority if the MDM endpoints are internet-reachable.
- Until patched, restrict the Apple MDM enrollment endpoints to trusted networks.
- Monitor the server for crashes and restarts, and check whether the server appears in your asset inventory and pinned container images.
Public exploits
PoC-in-GitHub, Metasploit and Exploit-DB list nothing for this CVE.
Research sources
- GitHub Security Advisory GHSA-x467-vgxf-2g6h github.com
- VulnCheck advisory www.vulncheck.com
- Fleet security advisories github.com
- Fleet release v4.92.0 github.com
- Vulners CVE record (CNA data) vulners.com
- VulDB CVE-2026-111923 vuldb.com
- RedPacket Security CVE alert www.redpacketsecurity.com
- CVE Threat Intelligence record cve.threatint.com
Researched and written up in English and German by an AI (Claude by Anthropic) based on NVD, CISA, EPSS and the sources listed. The vendor information is authoritative. Researched on 1 Nov 2026, 02:05.
Original description (NVD)
Fleet before 4.89.0 contains an unbounded recursion vulnerability in Apple MDM enrollment property list parsing that allows unauthenticated attackers to crash the server. Attackers can send a crafted binary plist payload of about 150 bytes to the enrollment endpoints, triggering exponential allocation or infinite recursion that exhausts CPU and memory.
Sources
The tracker combines official, freely usable data sources – updated continuously:
- NVD (NIST) – CVEs, rating (CVSS), affected products
- CISA KEV – vulnerabilities confirmed by CISA as actively exploited
- CISA Vulnrichment – CISA assessment (SSVC) in the official CVE record
- FIRST EPSS – probability of exploitation
- Microsoft MSRC – Patch Tuesday: vulnerabilities, severity, updates
- PoC-in-GitHub – public proof-of-concept repositories
- Metasploit (Rapid7) – modules of the Metasploit Framework
- Exploit-DB (OffSec) – archive of public exploits (links only)
- Patch days: official vendor pages (linked per vendor) (Vendor patch days)
This product uses data from the NVD API but is not endorsed or certified by the NVD. EPSS data © FIRST.org.
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