CVE-2026-63942
NVD analysis in progress
In the Linux kernel, the following vulnerability has been resolved: parport: Fix race between port and client registration The parport subsystem registers port devices before they are fully initialised, resulting in a race condition where client drivers such as lp can attach to ports that are not completely initialised or even being torn down. When the port and client drivers are built as modules and loaded around the same time during boot, this occasionally results in a crash. I was able to make this happen reliably in a VM with a PC-style parallel port by patching parport_pc to fail probing: > --- a/drivers/parport/parport_pc.c > +++ b/drivers/parport/parport_pc.c > @@ -2069,7 +2069,7 @@ static struct parport *__parport_pc_probe_port(unsigned long int base, > if (!p) > goto out3; > > - base_res = request_region(base, 3, p->name); > + base_res = NULL; > if (!base_res) > goto out4; > and then running: while true; do modprobe lp & modprobe parport_pc wait rmmod lp parport_pc done for a few seconds. In the long term I think port registration should be changed to put the call to device_add() inside parport_announce_port(), but since the latter currently cannot fail this will require changing all port drivers. For now, add a flag to indicate whether a port has been "announced" and only try to attach client drivers to ports when the flag is set.
What this means
- Exposure
- Exploitable with local access to the machine, with an ordinary user account and with no action from the victim.
- Impact
- An attacker can read sensitive data, modify or destroy data and take the service offline.
- Likelihood
- Its EPSS score stays low: nothing points to imminent exploitation, which is no reason to leave it unpatched.
What to doFold into the next patch cycle.
Read automatically from the CVSS vector, the weakness type (CWE) and the EPSS score. The technical description above remains the one published by NIST.