CVE-2026-45536
Description
Netty is a network application framework for development of protocol servers and clients. Prior to versions 4.1.135.Final and 4.2.15.Final, netty_unix_socket_recvFd sets msg_control to `char control[CMSG_SPACE(sizeof(int))]` (line 940) — 24 bytes on 64-bit Linux. A peer-sent SCM_RIGHTS cmsg carrying two ints has cmsg_len = CMSG_LEN(8) = 24, which fits exactly with no MSG_CTRUNC, so the kernel installs both fds in the receiving process. The subsequent check `cmsg->cmsg_len == CMSG_LEN(sizeof(int))` (line 972, expected 20) fails, the branch that would read the fd is skipped, and neither installed fd is closed. The for(;;) loop calls recvmsg again (non-blocking → EAGAIN → Java maps to 0 → read loop exits normally), leaving two leaked fds per message. There is no MSG_CTRUNC handling. Reachable via Epoll/KQueue DomainSocketChannel when the application opts into DomainSocketReadMode.FILE_DESCRIPTORS (non-default). Versions 4.1.135.Final and 4.2.15.Final patch the issue.
How to fix
- netty netty4.1.135, 4.2.15 or later
- io.netty:netty-transport-native-epoll4.2.15.Final, 4.1.135.Final or later
- io.netty:netty-transport-native-kqueue4.2.15.Final, 4.1.135.Final or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| netty netty | v < 4.1.135, 4.2.0 ≤ v < 4.2.15 | 4.1.135, 4.2.15 |
| io.netty:netty-transport-native-epollMaven | 4.2.0.Final ≤ v < 4.2.15.Final, v < 4.1.135.Final | 4.2.15.Final, 4.1.135.Final |
| io.netty:netty-transport-native-kqueueMaven | 4.2.0.Final ≤ v < 4.2.15.Final, v < 4.1.135.Final | 4.2.15.Final, 4.1.135.Final |
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