CVE-2026-89540

/// Technical description

In the Linux kernel, the following vulnerability has been resolved:

sunrpc: init gssp_lock before publishing proc entry

create_use_gss_proxy_proc_entry() publishes /proc/net/rpc/use-gss-proxy

via proc_create_data() before init_gssp_clnt() runs mutex_init() on

sn->gssp_lock. Once the dentry is linked under proc_subdir_lock it is

immediately reachable from userspace, so a write that lands in the

window drives set_gssp_clnt() into mutex_lock() on a zero-initialized

struct mutex.

create_use_gss_proxy_proc_entry(net)

proc_create_data("use-gss-proxy", ...) /* dentry live */

init_gssp_clnt(sn)

mutex_init(&sn->gssp_lock) /* too late */

write_gssp()

set_gssp_clnt(net)

mutex_lock(&sn->gssp_lock) /* uninitialized */

gssp_rpc_create(...)

sn->gssp_clnt = clnt

mutex_unlock(&sn->gssp_lock)

The window spans only the two statements between proc_create_data()

returning and init_gssp_clnt(), so a writer reac

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References