Cross-site scripting (XSS) vulnerability in tmui/dashboard/echo.jsp in the Configuration utility in F5 BIG-IP LTM, APM, ASM, GTM, and Link Controller 11.0.0 before 11.6.0 and 10.1.0 through 10.2.4, AAM 11.4.0 before 11.6.0, AFM and PEM 11.3.0 before 11.6.0, Analytics 11.0.0 through 11.5.1, Edge Gateway, WebAccelerator, and WOM 11.0.0 through 11.3.0 and 10.1.0 through 10.2.4, and PSM 11.0.0 through 11.4.1 and 10.1.0 through 10.2.4 and Enterprise Manager 3.0.0 through 3.1.1 and 2.1.0 through 2.3.0 allows remote attackers to inject arbitrary web script or HTML via unspecified vectors.

It is unexpected and not allowed to call TTY buffer helpers like ttyinsertflipstring concurrently. This may lead to crashes when ECHOing is enabled and concurrect writers call ptywrite in the meantime. In that case the two writers: the ECHOing from a workqueue and ptywrite from the process race and can overflow the corresponding TTY buffer.

An unprivileged local user could use this flaw to crash the system or, potentially, escalate their privileges on the system.

References: http://seclists.org/oss-sec/2014/q2/243