In the Linux kernel, the following vulnerability has been resolved:
udp: Fix wildcard bind conflict check when using hash2
When binding a udp_sock to a local address and port, UDP uses
two hashes (udptable->hash and udptable->hash2) for collision
detection. The current code switches to "hash2" when
hslot->count > 10.
"hash2" is keyed by local address and local port.
"hash" is keyed by local port only.
The issue can be shown in the following bind sequence (pseudo code):
bind(fd1, "[fd00::1]:8888")
bind(fd2, "[fd00::2]:8888")
bind(fd3, "[fd00::3]:8888")
bind(fd4, "[fd00::4]:8888")
bind(fd5, "[fd00::5]:8888")
bind(fd6, "[fd00::6]:8888")
bind(fd7, "[fd00::7]:8888")
bind(fd8, "[fd00::8]:8888")
bind(fd9, "[fd00::9]:8888")
bind(fd10, "[fd00::10]:8888")
/* Correctly return -EADDRINUSE because "hash" is used
* instead of "hash2". udp_lib_lport_inuse() detects the
* conflict.
*/
bind(fail_fd, "[::]:8888")
/* After one more socket is bound to "[fd00::11]:8888",
* hslot->count exceeds 10 and "hash2" is used instead.
*/
bind(fd11, "[fd00::11]:8888")
bind(fail_fd, "[::]:8888") /* succeeds unexpectedly */
The same issue applies to the IPv4 wildcard address "0.0.0.0"
and the IPv4-mapped wildcard address "::ffff:0.0.0.0". For
example, if there are existing sockets bound to
"192.168.1.[1-11]:8888", then binding "0.0.0.0:8888" or
"[::ffff:0.0.0.0]:8888" can also miss the conflict when
hslot->count > 10.
TCP inet_csk_get_port() already has the correct check in
inet_use_bhash2_on_bind(). Rename it to
inet_use_hash2_on_bind() and move it to inet_hashtables.h
so udp.c can reuse it in this fix.
References
Configurations
Configuration 1 (hide)
|
History
28 Apr 2026, 15:07
| Type | Values Removed | Values Added |
|---|---|---|
| First Time |
Linux
Linux linux Kernel |
|
| CVSS |
v2 : v3 : |
v2 : unknown
v3 : 5.5 |
| CPE | cpe:2.3:o:linux:linux_kernel:7.0:rc1:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:7.0:rc6:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:7.0:rc7:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:7.0:rc2:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:2.6.33:-:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:7.0:rc4:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:7.0:rc3:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:7.0:rc5:*:*:*:*:*:* |
|
| CWE | NVD-CWE-noinfo | |
| References | () https://git.kernel.org/stable/c/0a360f7f73a06ac88f18917055fbcc79694252d7 - Patch | |
| References | () https://git.kernel.org/stable/c/18d84c45def3671d5c89fbdd5d4ab8a3217fe4b4 - Patch | |
| References | () https://git.kernel.org/stable/c/2297e38114316b26ae02f2d205c49b5511c5ed55 - Patch | |
| References | () https://git.kernel.org/stable/c/d6ace0dbcbb7fd285738bb87b42b71b01858c952 - Patch | |
| References | () https://git.kernel.org/stable/c/e537dd15d0d4ad989d56a1021290f0c674dd8b28 - Patch | |
| References | () https://git.kernel.org/stable/c/f1bed05a832ae79be5f7a105da56810eaa59a5f1 - Patch |
22 Apr 2026, 14:16
| Type | Values Removed | Values Added |
|---|---|---|
| New CVE |
Information
Published : 2026-04-22 14:16
Updated : 2026-04-28 15:07
NVD link : CVE-2026-31503
Mitre link : CVE-2026-31503
CVE.ORG link : CVE-2026-31503
JSON object : View
Products Affected
linux
- linux_kernel
CWE