CVE-2026-98992: namespace: don't copy an unmounted mount tree
Noroxi assessment
Priority: Monitor (action score 0/100)
- The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
- Probability of exploitation in the next 30 days: 0.16% (FIRST EPSS).
- Fixed version: Linux Linux 7e037b1fd339d865737c8accd29abcf40130a5a0, 86a2d56b1960720bf1844441c0890621e9db2f25, 8bacbf6be959973b28b691713a872c12eae69eec.
Low priority for now. Upgrade to Linux Linux 7e037b1fd339d865737c8accd29abcf40130a5a0, 86a2d56b1960720bf1844441c0890621e9db2f25, 8bacbf6be959973b28b691713a872c12eae69eec or later.
Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it
Primary sources: NVD · CVE.org · FIRST EPSS
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.
- Published
- Oct 23, 2026
- Updated
- Oct 23, 2026
- EPSS
- 0.1% · 6th percentile
- CWE
- —
Report tools
Action score
0
Monitor
Low priority for now.
- CVSS
- 0 / 40 · —
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 0 / 30 · 0.1%
Get told when this record changes
- Not in KEV: no record of exploitation in the wild
- No public exploit code on record
- A fix has been released
If any of these changes, we'll tell you in the daily email digest.
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Noroxi analysis
What does it mean in your environment?
The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.
We use this product, ask for helpAffected systems
Is your version affected?
Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.
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Versions reported by the vendor
Affected version ranges reported by the assigning authority (Linux). Independent of NVD's CPE analysis and usually ahead of it.
Linux Linux
- 3.19affected
- e149ed2b805fefdccf7ccdfc19eca22fdd4514ac and later · before 86a2d56b1960720bf1844441c0890621e9db2f25affected · git
- e149ed2b805fefdccf7ccdfc19eca22fdd4514ac and later · before 7e037b1fd339d865737c8accd29abcf40130a5a0affected · git
- e149ed2b805fefdccf7ccdfc19eca22fdd4514ac and later · before b47b40c4f058418f9707454543179df240796aadaffected · git
- e149ed2b805fefdccf7ccdfc19eca22fdd4514ac and later · before 8d3527457e183cedee3003c2897314da49488311affected · git
- e149ed2b805fefdccf7ccdfc19eca22fdd4514ac and later · before 8bacbf6be959973b28b691713a872c12eae69eecaffected · git
- before 3.19not affected · semver
- 6.6.160 and later · up to and including 6.6.*not affected · semver
- 6.12.113 and later · up to and including 6.12.*not affected · semver
- 6.18.57 and later · up to and including 6.18.*not affected · semver
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| Debian:12 | linux | from 0 | — |
| Debian:13 | linux | before 6.12.113-1 | 6.12.113-1 |
| Debian:14 | linux | before 7.2.11-1 | 7.2.11-1 |
Same product
linux: all recordsOther highest-scoring records for the same primary product.
- CVE-2026-74705udp: fix potential use-after-free in tunnel segmentation40Plan
- CVE-2026-74612veth: fix skb length accounting after XDP frag adjustment40Plan
- CVE-2026-74475vxlan: use neigh_ha_snapshot() in route_shortcircuit()40Plan
Published before and after this one in the same product
- ← EarlierCVE-2026-98990Oct 23, 2026 · namespace: check a submount for references right before unmounting it0Monitor
- ← EarlierCVE-2026-98991Oct 23, 2026 · namespace: queue a mount only once for mount notifications31Monitor
- Later →CVE-2026-98993Oct 23, 2026 · namespace: don't inherit MNT_UMOUNT in clone_mnt()31Monitor
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
| Product / package | Fixed version | Source |
|---|---|---|
| Linux Linux | 7e037b1fd339d865737c8accd29abcf40130a5a0 | Vendor (CNA) |
| Linux Linux | 86a2d56b1960720bf1844441c0890621e9db2f25 | Vendor (CNA) |
| Linux Linux | 8bacbf6be959973b28b691713a872c12eae69eec | Vendor (CNA) |
| Linux Linux | 8d3527457e183cedee3003c2897314da49488311 | Vendor (CNA) |
| Linux Linux | b47b40c4f058418f9707454543179df240796aad | Vendor (CNA) |
| debian:linux | 6.12.113-1 · Debian:13 | Package registry (OSV) |
Exploit status
No known public exploit
No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.
Research context
For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.
Timeline
From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.
- Published
- Fix recordedsame day
- TodayOct 26, 2026+3 d
FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).
Patch and commit links
Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.
No commit or PR link among the references.
Credits
All researchersFinders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.
No credits in the CNA record.
Variant candidates
Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.
No nightly-computed relations.
Chain candidates
An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.
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Bug bounty scope
No known public program.
Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).
Technical details
No CVSS vector for this record, so attack conditions can't be derived.
Weakness class (CWE)
—
Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
MITRE has no CAPEC/ATT&CK mapping for this CWE.
Change log
- Exploit maturity— → none
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
Show all references (4 more)Show less
Vendor advisories and official records. Exploit/PoC links are deliberately left out.