Unknown

CVE-2026-63810 — block: Avoid mounting the bdev pseudo-filesystem in userspace

In the Linux kernel, the following vulnerability has been resolved: block: Avoid mounting the bdev pseudo-filesystem in userspace The bdev pseudo-filesystem is an internal kernel filesystem with which userspace should not interfere. Unregister it so that userspace cannot even attempt to mount it. This fixes a bug [1] that occurs when attempting to access files, because the system call move_mount() uses pointers declared in the inode_operations structure, which for the bdev pseudo-filesystem are always equal to 0. `inode->i_op = &empty_iops;` [1] BUG: kernel NULL pointer dereference, address: 0000000000000000 #PF: supervisor instruction fetch in kernel mode #PF: error_code(0x0010) - not-present page PGD 23380067 P4D 23380067 PUD 23381067 PMD 0 Oops: 0010 [#1] PREEMPT SMP KASAN NOPTI CPU: 2 PID: 17125 Comm: syz-executor.0 Not tainted 6.1.155-syzkaller-00350-g84221fde2681 #0 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 04/01/2014 RIP: 0010:0x0 Call Trace: <TASK> lookup_open.isra.0+0x700/0x1180 fs/namei.c:3460 open_last_lookups fs/namei.c:3550 [inline] path_openat+0x953/0x2700 fs/namei.c:3780 do_filp_open+0x1c5/0x410 fs/namei.c:3810 do_sys_openat2+0x171/0x4d0 fs/open.c:1318 do_sys_open fs/open.c:1334 [inline] __do_sys_openat fs/open.c:1350 [inline] __se_sys_openat fs/open.c:1345 [inline] __x64_sys_openat+0x13c/0x1f0 fs/open.c:1345 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x35/0x80 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x6e/0xd8 Found by Linux Verification Center (linuxtesting.org) with Syzkaller.

Published Jul 19, 2026 · Updated Oct 15, 2026 · Sources: NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP, GitHub Security Advisories · CNA: Linux

Low

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

No exploitation signal in the sources consulted so far.

How the score was calculated

EPSS 0.2% (30-day exploitation probability)+2

The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

Exploitation

Not confirmed

Not in CISA KEV — an absence of record, not proof it is unexploited.

EPSS FIRST

0.21%

ahead of 10% of scored CVEs · Oct 15, 2026

Affects

Linux

CVSS base

—

Score not published yet.

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

No fix documented by the sources we poll. That does not mean none exists: check the vendor advisory.

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

Identify exposed assets running the affected vendor/product/version combinations (Linux Linux).
No fix documented in the sources: reduce exposure and monitor the vendor advisory.
Search available logs for exploit probes, errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

Vendor	Product	Versions	Status	Source
Linux	Linux	≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and < 3d3fcf23993bb756de2f912ab631cfdcc4746554≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and < 99cde0a7b1e98fd3970aabef1300918e91698dd5≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and < 1a02a5028bd6dead1f8503854ef3168d651cd417≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and < 197971e6ffc0a6356b2ba2b22beb42bc0f7e412d≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and < 3804e6de30ae7b053d53341d9d6944356cf23b40≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and < 717f721eb67d2dacd3ed5f7495aef2f442e84ce4≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and < f73aa66dffcb8e61e78f01b56163ec16a15d06d2version 2.6.12	Vulnerable	CVE Program (cve.org) e CISA ADP

EPSS over time FIRST

Oct 14, 2026 → Oct 15, 2026 · 2 reading(s) · max 0.21%

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

Not enough vector or weakness data: use the affected application’s logs as a starting point.

application logs

Timeline

What happened to this CVE, newest first.

2026
Record published
Oct 15, 2026
Affected products added · linux/linux
Oct 15, 2026 · CVE Program (cve.org) e CISA ADP
Source status changed · → Awaiting Analysis
Oct 15, 2026 · NIST National Vulnerability Database
Record created in this database
Oct 15, 2026 · Alertas do Telegram
CVE published
Jul 19, 2026 · Linux

Source activity

Repeated readings are counted rather than listed.

2× References added · Oct 15, 2026 – Oct 15, 2026
1× Official description updated · Oct 15, 2026 – Oct 15, 2026

References

11 on the record

git.kernel.org/stable/c/197971e6ffc0a6356b2ba2b22beb42bc0f7e412d
NIST National Vulnerability Database
git.kernel.org/stable/c/3804e6de30ae7b053d53341d9d6944356cf23b40
NIST National Vulnerability Database
cert-portal.siemens.com/productcert/html/ssa-457936.html
NIST National Vulnerability Database
git.kernel.org/stable/c/99cde0a7b1e98fd3970aabef1300918e91698dd5
NIST National Vulnerability Database
git.kernel.org/stable/c/1a02a5028bd6dead1f8503854ef3168d651cd417
NIST National Vulnerability Database
cert-portal.siemens.com/productcert/html/ssa-019113.html
NIST National Vulnerability Database
git.kernel.org/stable/c/3d3fcf23993bb756de2f912ab631cfdcc4746554
NIST National Vulnerability Database
nvd.nist.gov/vuln/detail/CVE-2026-63810
GitHub Security Advisories
git.kernel.org/stable/c/717f721eb67d2dacd3ed5f7495aef2f442e84ce4
NIST National Vulnerability Database
git.kernel.org/stable/c/f73aa66dffcb8e61e78f01b56163ec16a15d06d2
NIST National Vulnerability Database
github.com/advisories/GHSA-xxr8-hfww-qgf6
GitHub Security Advisories

Elsewhere on this site

Linux
every CVE for this vendor

Related CVEs (same products)

Critical CVE-2026-99999 ipv4: validate checksum_start before completing checksum 15h
Unknown CVE-2026-98432 ipv4: free inet_opt and ireq_opt after an RCU grace period 15h
Unknown CVE-2026-98426 wifi: mwifiex: fix IRQ leak using wrong index in MSI-X error path 1d
Unknown CVE-2026-98424 wifi: cfg80211: undo netns switch if renaming the wiphy fails 1d
Unknown CVE-2026-98425 wifi: mac80211: don't warn when an IBSS has no channel to scan 1d
Unknown CVE-2026-98427 net/sched: codel: bound the dropping loop per dequeue call 1d

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

No CVSS score published by NVD, the CNA, CISA or GitHub so far.
No fixed version, patch or mitigation documented.
No CISA SSVC assessment.
No CWE classification.
No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2026-63810 is "block: Avoid mounting the bdev pseudo-filesystem in userspace", rated Unknown. It affects Linux (Linux); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. EPSS 0.21% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

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