On Wed, Aug 12, 2026 at 05:10:17PM +0200, Peter Krempa via Devel wrote:
From: Peter Krempa <pkrempa@redhat.com>
CVE-2026-18917
The RPC handler 'remoteDispatchNodeGetFreePages' multiplies the 'npages' argument with the 'cellcount' argument passed to 'virNodeGetFreePages', both of which are declared as 'unsigned int' to both do an RPC limit check against the 'REMOTE_NODE_MAX_CELLS' constant and then to allocate the memory to hold the result from the actual hypervisor driver.
Since both the values are 'unsigned int' the product is also unsigned int so big enough numbers can overflow, both passing the check and also allocating not enough memory for the result. The hypervisor driver assumes that the passed buffer is large enough and overwrites memory.
When this happens the the hypervisor daemon crashes.
This can be triggered e.g. by passing 1023 and 4198405 as values which multiply to 1019 after wrapping to 32 bit unsigned value.
Use the VIR_INT_MULTIPLY_OVERFLOW macro in the check to avoid the issue the same way as we do for other APIs doing multiplication of arguments to determine amount of required memory.
Fixes: 34f2d0319d2098c77c8cc27d8350616029125a2b (v1.2.5-164-g34f2d0319d) Closes: https://gitlab.com/libvirt/libvirt/-/work_items/903 Signed-off-by: Peter Krempa <pkrempa@redhat.com> --- src/remote/remote_daemon_dispatch.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-)
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com> With regards, Daniel -- |: https://berrange.com ~~ https://hachyderm.io/@berrange :| |: https://libvirt.org ~~ https://entangle-photo.org :| |: https://pixelfed.art/berrange ~~ https://fstop138.berrange.com :|