Vulnerability · Published Jun 12, 2026 · Assigned by GitHub_M
CVE-2026-45536Netty: Unix-socket fd receive leaks descriptors when peer sends two at once
Medium 4.0
In plain English
A medium-severity information exposure in netty from netty. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.1% (higher than 3% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official 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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | netty | no fix listed | DEBIAN-CVE-2026-45536 |
| Debian:13 | netty | no fix listed | DEBIAN-CVE-2026-45536 |
| Debian:14 | netty | no fix listed | DEBIAN-CVE-2026-45536 |
| Maven | io.netty:netty-transport-native-epoll | 4.2.15.Final | GHSA-w573-9ffj-6ff9 |
| Maven | io.netty:netty-transport-native-epoll | 4.1.135.Final | GHSA-w573-9ffj-6ff9 |
| Maven | io.netty:netty-transport-native-kqueue | 4.1.135.Final | GHSA-w573-9ffj-6ff9 |
| Maven | io.netty:netty-transport-native-kqueue | 4.2.15.Final | GHSA-w573-9ffj-6ff9 |
| Ubuntu:25.10 | netty | no fix listed | UBUNTU-CVE-2026-45536 |
| Ubuntu:26.10 | netty | no fix listed | UBUNTU-CVE-2026-45536 |
Affected products (as reported)
Weakness: CWE-200, CWE-772 · Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
References
- https://github.com/netty/netty/security/advisories/GHSA-w573-9ffj-6ff9 x_refsource_CONFIRM
- https://github.com/netty/netty/releases/tag/netty-4.1.135.Final x_refsource_MISC
- https://github.com/netty/netty/releases/tag/netty-4.2.15.Final x_refsource_MISC