Last Modified: Oct 16, 2026
Affected Product(s):
BIG-IP TMOS
Known Affected Versions:
21.1.0, 21.1.0.1, 21.1.0.2, 21.1.0.3
Opened: Jun 08, 2026 Severity: 3-Major
MCPD crashes unexpectedly with a segmentation fault (SIGSEGV), generating a core file in /var/core/ The following entry is observed in /var/log/kern.log: mcpd_worker_1[11387]: segfault at 22 ip 0000000000669eda sp 00007fd8a38984f0 error 4 in mcpd[400000+64c000]
- MCPD process crashes and restarts - Traffic disrupted during mcpd restart
- BIG-IP version 21.x with multi-threaded mcpd enabled (mcpd.workerthreads >= 1) - Worker thread processing a cid_query_non_default query concurrently with main thread activity (config modification, folder operations, or other ExtremeDB writes) - [Add any specific conditions observed, e.g.: HA enabled, config-sync active, high object count, concurrent tmsh/REST API sessions]
NA
None