Mooncake Transfer Engine: Out-of-bounds read in P2P handshake allows remote crash
Summary
Mooncake Transfer Engine before 0.3.12 contains an out-of-bounds read in the readString function that is triggered by a zero-length handshake frame. An unauthenticated remote attacker who can reach the handshake port, which listens on all interfaces, can crash the hosting process, such as an SGLang inference server. The impact is a denial of service, not code execution or data theft.
Affected
- Mooncake Transfer Engine (mooncake-transfer-engine) versions before 0.3.12
- Vendor range per GitHub issue #4452: up to and including 0.3.11.post1
- Note: sources disagree on the exact range; later builds such as 0.3.12.post1 should be checked against current advisories
Fixed in
- Fixed in 0.3.12 (commit c142b40590259360196d8e504b2193382529e7b4 adds a zero-length check in readString)
- No vendor security advisory found; verify the current release
Workaround
- No vendor-documented workaround found.
- Restrict the P2P handshake port range (default 15000-17000 per the issue) to trusted hosts with a host or network firewall. Do not expose it to the internet.
Exploitation
- Unauthenticated, network-reachable (AV:N, PR:N), low complexity; a single eight-byte frame is enough to crash the process.
- CISA SSVC: exploitation status PoC, automatable: yes, technical impact: partial.
- No public PoC confirmed by the sources; not listed as known exploited; EPSS 0.00366.
Our recommendation
- Inventory all hosts and container images that run mooncake-transfer-engine (check pip lockfiles).
- Upgrade to the current release, not only 0.3.12.
- Restrict the handshake port range now, including on internal networks.
- Monitor for unexpected restarts of inference services.
Public exploits
PoC-in-GitHub, Metasploit and Exploit-DB list nothing for this CVE.
Research sources
- Mooncake GitHub issue #4452 github.com
- Fix commit c142b40 github.com
- VulnCheck advisory www.vulncheck.com
- OSV entry CVE-2026-104433 osv.dev
- Mooncake project repository github.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, 05:43.
Original description (NVD)
Mooncake transfer engine before 0.3.12 contains an out-of-bounds read vulnerability in the readString function of include/common.h that allows unauthenticated attackers to crash the service by sending a zero-length handshake frame. Attackers can connect to the handshake port listening on all interfaces and send an eight-byte frame to terminate the hosting process, such as an SGLang inference server.
NVD references (5)
- https://github.com/kvcache-ai/Mooncake
- https://github.com/kvcache-ai/Mooncake/commit/c142b40590259360196d8e504b2193382529e7b4
- https://github.com/kvcache-ai/Mooncake/issues/4452
- https://www.vulncheck.com/advisories/mooncake-before-0.3.12-out-of-bounds-read-via-p2p-handshake-readstring
- https://github.com/kvcache-ai/Mooncake/issues/4452
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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