High

CVE-2026-63813 — Revert "f2fs: remove non-uptodate folio from the page cache in move_data_block"

In the Linux kernel, the following vulnerability has been resolved: Revert "f2fs: remove non-uptodate folio from the page cache in move_data_block" This reverts commit 9609dd704725a40cd63d915f2ab6c44248a44598. The kernel panics are keeping to be reported especially when the f2fs partition get almost full. By investigation, we find that the reason is one f2fs page got freed to buddy without being deleted from LRU and the root cause is the race happened in [2] which is enrolled by this commit. There are 3 race processes in this scenario, please find below for their main activities. The changed code in move_data_block() lets the GC path evict the tail-end folio from the page cache through folio_end_dropbehind(). Once folio_unmap_invalidate() removes the folio from mapping->i_pages, the page-cache references for all pages in the folio are dropped. The folio is then kept alive only by temporary external references, which allows a later split to operate on a folio whose subpages are no longer protected by page-cache references. After the page-cache references are gone, split_folio_to_order() can split the big folio into individual pages and put the resulting subpages back on the LRU. For tail pages beyond EOF, split removes them from the page cache and drops their page-cache references. A tail page can then remain on the LRU with PG_lru set while holding only the split caller's temporary reference. When free_folio_and_swap_cache() drops that final reference, the page enters the final folio_put() release path. In parallel, folio_isolate_lru() can observe the same tail page with a non-zero refcount and PG_lru set. It clears PG_lru before taking its own reference. If this races with the final folio_put() from the split path, __folio_put() sees PG_lru already cleared and skips lruvec_del_folio(). The page is then freed back to the allocator while its lru links are still present in the LRU list. A later LRU operation on a neighboring page detects the stale link and reports list corruption. [1] [ 22.486082] list_del corruption. next->prev should be fffffffec10e0ac8, but was dead000000000122. (next=fffffffec10e0a88) [ 22.486130] ------------[ cut here ]------------ [ 22.486134] kernel BUG at lib/list_debug.c:67! [ 22.486141] Internal error: Oops - BUG: 00000000f2000800 [#1] SMP [ 22.488502] Tainted: [W]=WARN, [O]=OOT_MODULE [ 22.488506] Hardware name: Spreadtrum UMS9230 1H10 SoC (DT) [ 22.488511] pstate: 604000c5 (nZCv daIF +PAN -UAO -TCO -DIT -SSBS BTYPE=--) [ 22.488517] pc : __list_del_entry_valid_or_report+0x14c/0x154 [ 22.488531] lr : __list_del_entry_valid_or_report+0x14c/0x154 [ 22.488539] sp : ffffffc08006b830 [ 22.488542] x29: ffffffc08006b868 x28: 0000000000003020 x27: 0000000000000000 [ 22.488553] x26: 0000000000000000 x25: 0000000000000004 x24: fffffffec10e0ac0 [ 22.488564] x23: 00000000000000e8 x22: 0000000000000024 x21: dead000000000122 [ 22.488574] x20: fffffffec10e0a88 x19: fffffffec10e0ac8 x18: ffffffc080061060 [ 22.488585] x17: 20747562202c3863 x16: 6130653031636566 x15: 0000000000000058 [ 22.488595] x14: 0000000000000004 x13: ffffff80f91e0000 x12: 0000000000000003 [ 22.488605] x11: 0000000000000003 x10: 0000000000000001 x9 : ffe85721f0e25f00 [ 22.488615] x8 : ffe85721f0e25f00 x7 : 0000000000000000 x6 : 6c65645f7473696c [ 22.488625] x5 : ffffffed39b23026 x4 : 0000000000000000 x3 : 0000000000000010 [ 22.488636] x2 : 0000000000000000 x1 : 0000000000000000 x0 : 000000000000006d [ 22.488647] Call trace: [ 22.488651] __list_del_entry_valid_or_report+0x14c/0x154 (P) [ 22.488661] __folio_put+0x2bc/0x434 [ 22.488670] folio_put+0x28/0x58 [ 22.488678] do_garbage_collect+0x1a34/0x2584 [ 22.488689] f2fs_gc+0x230/0x9b4 [ 22.488697] f2fs_fallocate+0xb90/0xdf4 [ 22.488706] vfs_fallocate+0x1b4/0x2bc [ 22.488716] __arm64_sys_fallocate+0x44/0x78 [ 22.488725] invoke_syscall+0x58/0xe4 [ 22.488732] do_el0_svc+0x48/0xdc [ 22.488739] el0 ---truncated---

Published Jul 19, 2026 · Updated Oct 15, 2026 · Sources: NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP · 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 0.1% (30-day exploitation probability)+0
Technical severity (high)+6

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

0.13%

ahead of 2% of scored CVEs · Oct 15, 2026

Affects

Linux

CVSS base

7.8

High · 2 source(s)

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	≥ 5a4d3968cf820686400fc757a4512dcaddd84846 and < 1991d49433e90b2202de2fe90be3c24161873d7c≥ 9609dd704725a40cd63d915f2ab6c44248a44598 and < 6e035dae44154af4dd7bdb8ef7a1118c0b5f17b6≥ 9609dd704725a40cd63d915f2ab6c44248a44598 and < ccaba785821970f422c47770331c7e3271763f17version 7.0	Vulnerable	CVE Program (cve.org) e CISA ADP

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Attack vector

Local

Attack complexity

Low

Privileges required

Low

User interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Every base score collected

Sources score independently and may disagree; each row says who scored it and under which version.

Score	Version	Severity	Expl.	Impact	Scored by
7.8	CVSS 3.1	High	1.8	5.9	416baaa9-dc9f-4396-8d5f-8c081fb06d67 via NIST National Vulnerability Database
7.8	CVSS 3.1	High	—	—	Linux via CVE Program (cve.org) e CISA ADP

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H (score shown at the top: 416baaa9-dc9f-4396-8d5f-8c081fb06d67)

Detection

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

Local/physical vector: focus on endpoint telemetry (EDR) from affected hosts.

endpoint telemetry (EDR)

Timeline

What happened to this CVE, newest first.

2026
Affected products added · linux/linux
Oct 15, 2026 · CVE Program (cve.org) e CISA ADP
Record published
Oct 15, 2026
CVSS changed · 7.8
Oct 15, 2026 · NIST National Vulnerability Database
Source status changed · → Awaiting Analysis
Oct 15, 2026 · NIST National Vulnerability Database
Record created in this database
Oct 15, 2026 · NIST National Vulnerability Database
CVE published
Jul 19, 2026 · Linux

Source activity

Repeated readings are counted rather than listed.

1× Official description updated · Oct 15, 2026 – Oct 15, 2026

References

3 on the record

git.kernel.org/stable/c/6e035dae44154af4dd7bdb8ef7a1118c0b5f17b6
NIST National Vulnerability Database
git.kernel.org/stable/c/1991d49433e90b2202de2fe90be3c24161873d7c
NIST National Vulnerability Database
git.kernel.org/stable/c/ccaba785821970f422c47770331c7e3271763f17
NIST National Vulnerability Database

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 1d
Unknown CVE-2026-98432 ipv4: free inet_opt and ireq_opt after an RCU grace period 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-2026-98426 wifi: mwifiex: fix IRQ leak using wrong index in MSI-X error path 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 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-2026-63813 is "Revert "f2fs: remove non-uptodate folio from the page cache in move_data_block"", rated High. It affects Linux (Linux); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 7.8 describes technical severity. EPSS 0.13% 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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