Answer in brief
CVE-2026-98992 records a Unknown severity vulnerability in namespace: don't copy an unmounted mount tree. 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 | >=e149ed2b805fefdccf7ccdfc19eca22fdd4514ac <86a2d56b1960720bf1844441c0890621e9db2f25 || >=e149ed2b805fefdccf7ccdfc19eca22fdd4514ac <7e037b1fd339d865737c8accd29abcf40130a5a0 || >=e149ed2b805fefdccf7ccdfc19eca22fdd4514ac <b47b40c4f058418f9707454543179df240796aad || >=e149ed2b805fefdccf7ccdfc19eca22fdd4514ac <8d3527457e183cedee3003c2897314da49488311 || >=e149ed2b805fefdccf7ccdfc19eca22fdd4514ac <8bacbf6be959973b28b691713a872c12eae69eec | 86a2d56b1960720bf1844441c0890621e9db2f25, 7e037b1fd339d865737c8accd29abcf40130a5a0, b47b40c4f058418f9707454543179df240796aad, 8d3527457e183cedee3003c2897314da49488311, 8bacbf6be959973b28b691713a872c12eae69eec |
| Linux/Linuxgeneric | 3.19 | 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: don't copy an unmounted mount tree may_copy_tree() accepts a mount whose root is an nsfs or pidfs file before it checks whether that mount is mounted. This exception exists for nsfs and pidfs mounts. They are part of no mount namespace so neither check_mnt() nor is_mounted() would let them through and bind-mounting a nsfsfd or a pidfd wouldn't work. Problem is that exception also admits a bind mount of such a file when it was lazily unmounted and is only kept alive by a file descriptor: mount --bind /proc/self/ns/net /tmp/x exec 3< /tmp/x umount -l /tmp/x mount --rbind /proc/self/fd/3 /tmp/y With MS_REC or AT_RECURSIVE copy_tree() doesn't stop at the unmounted mount. It copies every mount that stayed attached to it as well. So if you have a bunch of overmounts over the nsfsfd or the pidfd the whole unmounted stack is copied. That's a bug. So refuse to walk an unmounted tree. Copying its root alone stays possible. So a bind mount of a namespace that is gone can still be recreated from a file descriptor on the old one. The file descriptor pins that mount and its root and __has_locked_children() only reads the direct children which don't leave the parent's list without namespace_sem. The internal mounts carry MNT_NS_INTERNAL instead of NULL and are still walked. Copying an unmounted tree recursively fails with EINVAL.
Quoted source text, attributed separately from HOL analysis.