NVD / CVE Program· CNA Linux

CVE-2026-68148: fscrypt: Add missing superblock check in find_or_insert_direct_key()

Noroxi assessment

Priority: Monitor (action score 31/100)

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: 0.09% (FIRST EPSS).
Someone with local access to the system can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
Fixed version: Linux Linux 330249609b70778094a7a36f5b6bcfa6362121d4, 466f187b501a5ac8e1ea2ccf3ccd5c46108d8830, 95376fe9c145be35566991df99c53134943d992f; azl3 kernel 6.6.143.1-1 on Azure Linux 3.0 6.6.150.1-1.
Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to Linux Linux 330249609b70778094a7a36f5b6bcfa6362121d4, 466f187b501a5ac8e1ea2ccf3ccd5c46108d8830, 95376fe9c145be35566991df99c53134943d992f; azl3 kernel 6.6.143.1-1 on Azure Linux 3.0 6.6.150.1-1 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: fscrypt: Add missing superblock check in find_or_insert_direct_key() The legacy 'fscrypt_direct_keys' table caches master keys that are used by v1 encryption policies that have FSCRYPT_POLICY_FLAG_DIRECT_KEY. It's just a global table for all filesystems (since the keys can be provided by the legacy process-subscribed keyrings mechanism, which makes it difficult to reuse super_block::s_master_keys). The entries in it ('struct fscrypt_direct_key') do contain a super_block pointer, though, for passing to fscrypt_destroy_inline_crypt_key() when the last inode that references the key is evicted. However, when finding the fscrypt_direct_key for an inode, we weren't actually comparing the super_block pointer. As a result, inodes with different super_blocks could point to the same fscrypt_direct_key. That could extend the lifetime of a fscrypt_direct_key beyond the super_block it points to, causing a use-after-free later. Fix this by creating distinct fscrypt_direct_key structs for distinct super_block structs. Note that this problem doesn't exist in the v2 policy equivalent ("per-mode keys"), since the data structures there are per super_block.

HighCVSS 7.8 · v3.1—No exploit Fix available

Memory safety

Published: Aug 10, 2026
Updated: Oct 19, 2026
EPSS: 0.0% · 0th percentile
CWE: CWE-416

Report tools

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Action score

Monitor

Low priority for now.

CVSS: 31 / 40 · 7.8 / 10
CISA KEV: 0 / 30 · Not listed
EPSS: 0 / 30 · 0.0%

CISA SSVC decision

Exploitation: none
Automatable: no
Technical impact: total

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD: —
CNA · Linux: 7.8; NVD has not scored this yet; the score shown is the CNA’s.

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

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.

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Affected 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.

—

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
- 6.1affected
- 22e9947a4b2ba255888541bd0111cf00b9b16586 and later · before 965b5bc8cf5031225e057979ce660fec2bd5fbfcaffected · git
- 22e9947a4b2ba255888541bd0111cf00b9b16586 and later · before 330249609b70778094a7a36f5b6bcfa6362121d4affected · git
- 22e9947a4b2ba255888541bd0111cf00b9b16586 and later · before deff41898a5ae3a47db5fa1896a494aa95efda5daffected · git
- 22e9947a4b2ba255888541bd0111cf00b9b16586 and later · before 95376fe9c145be35566991df99c53134943d992faffected · git
- 22e9947a4b2ba255888541bd0111cf00b9b16586 and later · before 466f187b501a5ac8e1ea2ccf3ccd5c46108d8830affected · git
- 22e9947a4b2ba255888541bd0111cf00b9b16586 and later · before b5fa40226e71c17847b9ff2816c6ca4133d0d994affected · git
- before 6.1not affected · semver
- 6.1.183 and later · up to and including 6.1.*not affected · semver
- 6.6.148 and later · up to and including 6.6.*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	before 6.1.187-1	6.1.187-1
Debian:12	linux-6.12	before 6.12.101-1~deb12u1	6.12.101-1~deb12u1
Debian:13	linux	before 6.12.101-1	6.12.101-1
Debian:14	linux	before 7.1.6-1	7.1.6-1

Same product

linux: all records

Other highest-scoring records for the same primary product.

CVE-2026-74705udp: fix potential use-after-free in tunnel segmentation
40Plan
CVE-2026-74612veth: fix skb length accounting after XDP frag adjustment
40Plan
CVE-2026-74475vxlan: use neigh_ha_snapshot() in route_shortcircuit()
40Plan

Published before and after this one in the same product

← EarlierCVE-2026-68144Aug 10, 2026 · phonet: pep: fix use-after-free in pep_get_sb()
39Monitor
← EarlierCVE-2026-68145Aug 10, 2026 · iomap: fix out-of-bounds bitmap_set() with zero-length range
31Monitor
Later →CVE-2026-68149Aug 10, 2026 · fs: preserve ACL_DONT_CACHE state in forget_cached_acl()
33Monitor

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	330249609b70778094a7a36f5b6bcfa6362121d4	Vendor (CNA)
Linux Linux	466f187b501a5ac8e1ea2ccf3ccd5c46108d8830	Vendor (CNA)
Linux Linux	95376fe9c145be35566991df99c53134943d992f	Vendor (CNA)
Linux Linux	965b5bc8cf5031225e057979ce660fec2bd5fbfc	Vendor (CNA)
Linux Linux	b5fa40226e71c17847b9ff2816c6ca4133d0d994	Vendor (CNA)
Linux Linux	deff41898a5ae3a47db5fa1896a494aa95efda5d	Vendor (CNA)
azl3 kernel 6.6.143.1-1 on Azure Linux 3.0	6.6.150.1-1 · CBL-Mariner Releases	Microsoft (MSRC)
debian:linux	6.1.187-1 · Debian:12	Package registry (OSV)
debian:linux-6.12	6.12.101-1~deb12u1 · Debian:12	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.

No dated events beyond publication.

EPSS, last 120 days

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 researchers

Finders, 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.

CVE-2026-681170 days aparttipc: clear sock->sk on the failed-insert path in tipc_sk_create()
39Monitor
CVE-2026-681270 days apartila: reload IPv6 header after pskb_may_pull in checksum adjust
39Monitor
CVE-2026-681440 days apartphonet: pep: fix use-after-free in pep_get_sb()
39Monitor
CVE-2026-681560 days apartlibceph: refresh auth->authorizer_buf{,_len} after authorizer update
39Monitor
CVE-2026-683810 days apartksmbd: pin conn during async oplock break notification
39Monitor
CVE-2026-684260 days apartxfrm: fix stale skb->prev after async crypto steals a GSO segment
39Monitor

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

National notice (Türkiye Cybersecurity Directorate / USOM)

Official security notices citing this record; remediation advice is on the agency's page.

TR-26-0800 · Aug 11, 2026(Linux Kernel Güvenlik Bildirimi)

All national notices →

Technical details

Attack conditions

Someone with local access to the system can trigger it.
A low-privileged account is enough.
No user action is required.
No special conditions are required; it is repeatable.

If successful

Confidentiality: high · data can be read
Integrity: high · data or configuration can be modified
Availability: high · the service can be disrupted

Attack vector: Local
Attack complexity: Low
Privileges required: Low
User interaction: None
Scope: Unchanged
Confidentiality impact: High
Integrity impact: High
Availability impact: High

Weakness class (CWE)

CWE-416 · Use After Free

CVSS vector

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

nvd-secondary

Root cause

After a memory region is freed, another reference pointing to it is still used. By then, the same region may have been allocated for different data.

The bug in code

The whole CWE-416 class

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

Vulnerable

1free(dev->buf);
2/* ... another thread is still running ... */
3process(dev->buf);

Fixed

1lock(&dev->lock);
2free(dev->buf);
3dev->buf = NULL;
4unlock(&dev->lock);

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

SSVC exploitation— → noneOct 16, 2026, 5:07 PM UTC
Fix✗ → ✓Sep 28, 2026, 10:07 PM UTC

For records you follow, these changes also arrive as notifications. →

References

git.kernel.org/stable/c/330249609b70778094a7a36f5b6bcfa6362121d4

Show all references (5 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records