Answer in brief
CVE-2026-98979 records a Unknown severity vulnerability in namespace: refuse an automount below a mount that is in no namespace. The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
A CVSS score is not reported in the current record. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| Linux/Linuxgeneric | >=df820f8de4e481222b17f9bcee7b909ae8167529 <95fb7c259b86f5521f04973040ad492f2bef6f82 || >=df820f8de4e481222b17f9bcee7b909ae8167529 <35f2013f83ef16f9f0331c4c3a8e8d161580d574 || >=df820f8de4e481222b17f9bcee7b909ae8167529 <494c57572d2d5bc2839553ed41aabe92ed0f587c || >=df820f8de4e481222b17f9bcee7b909ae8167529 <776e20e4fdc23c23687b511ffdc80047878049d3 || >=df820f8de4e481222b17f9bcee7b909ae8167529 <ba985ce08471c555af2a2fbe217c1bc2e72a6d8c | 95fb7c259b86f5521f04973040ad492f2bef6f82, 35f2013f83ef16f9f0331c4c3a8e8d161580d574, 494c57572d2d5bc2839553ed41aabe92ed0f587c, 776e20e4fdc23c23687b511ffdc80047878049d3, ba985ce08471c555af2a2fbe217c1bc2e72a6d8c |
| Linux/Linuxgeneric | 5.8 | Not reported |
Published upstream
Oct 23, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Oct 23, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Oct 23, 2026
In the Linux kernel, the following vulnerability has been resolved: namespace: refuse an automount below a mount that is in no namespace It's possible to add autmounts even when the parent mount isn't in the mount namespace of the caller. The only requirement we have is that the parent mount namespace must not be NULL, i.e., unmounted. Problem is that clone_private_mount() has MNT_NS_INTERNAL which makes that trivially true. So that passes the test and attach_recursive_mnt() accepts that as a mount point and funny enough, count_mounts() dereferences MNT_NS_INTERNAL. The problem is it is an error pointer... So we can reach this in userspace via fanotify. A filesystem mark on the lower filesystem of an overlay reports paths on the layer clone and reading the event hands out a descriptor on it. For example with debugfs as the lower layer it goes kaboom: openat(evfd, "tracing", O_DIRECTORY) Oops: general protection fault KASAN: null-ptr-deref in range [0x1d0-0x1d7] RIP: 0010:count_mounts+0x35/0x200 attach_recursive_mnt finish_automount And since that sleeping beauty happens under namespace_sem held for writing every mount operation on the system blocks from then on. Congrats. Use is_mounted() instead which rejects unmounted and internal mounts alike. The open fails with EINVAL just as it did before clone_private_mount() used MNT_NS_INTERNAL.
Quoted source text, attributed separately from HOL analysis.