In the Linux kernel, the following vulnerability has been resolved:
ext4: fix out of bounds punch offset
Punching a hole with a start offset that exceeds max_end is not
permitted and will result in a negative length in the
truncate_inode_partial_folio() function while truncating the page cache,
potentially leading to undesirable consequences.
A simple reproducer:
truncate -s 9895604649994 /mnt/foo
xfs_io -c "pwrite 8796093022208 4096" /mnt/foo
xfs_io -c "fpunch 8796093022213 25769803777" /mnt/foo
kernel BUG at include/linux/highmem.h:275!
Oops: invalid opcode: 0000 [#1] SMP PTI
CPU: 3 UID: 0 PID: 710 Comm: xfs_io Not tainted 6.15.0-rc3
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-2.fc40 04/01/2014
RIP: 0010:zero_user_segments.constprop.0+0xd7/0x110
RSP: 0018:ffffc90001cf3b38 EFLAGS: 00010287
RAX: 0000000000000005 RBX: ffffea0001485e40 RCX: 0000000000001000
RDX: 000000000040b000 RSI: 0000000000000005 RDI: 000000000040b000
RBP: 000000000040affb R08: ffff888000000000 R09: ffffea0000000000
R10: 0000000000000003 R11: 00000000fffc7fc5 R12: 0000000000000005
R13: 000000000040affb R14: ffffea0001485e40 R15: ffff888031cd3000
FS: 00007f4f63d0b780(0000) GS:ffff8880d337d000(0000)
knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000001ae0b038 CR3: 00000000536aa000 CR4: 00000000000006f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
truncate_inode_partial_folio+0x3dd/0x620
truncate_inode_pages_range+0x226/0x720
? bdev_getblk+0x52/0x3e0
? ext4_get_group_desc+0x78/0x150
? crc32c_arch+0xfd/0x180
? __ext4_get_inode_loc+0x18c/0x840
? ext4_inode_csum+0x117/0x160
? jbd2_journal_dirty_metadata+0x61/0x390
? __ext4_handle_dirty_metadata+0xa0/0x2b0
? kmem_cache_free+0x90/0x5a0
? jbd2_journal_stop+0x1d5/0x550
? __ext4_journal_stop+0x49/0x100
truncate_pagecache_range+0x50/0x80
ext4_truncate_page_cache_block_range+0x57/0x3a0
ext4_punch_hole+0x1fe/0x670
ext4_fallocate+0x792/0x17d0
? __count_memcg_events+0x175/0x2a0
vfs_fallocate+0x121/0x560
ksys_fallocate+0x51/0xc0
__x64_sys_fallocate+0x24/0x40
x64_sys_call+0x18d2/0x4170
do_syscall_64+0xa7/0x220
entry_SYSCALL_64_after_hwframe+0x76/0x7e
Fix this by filtering out cases where the punching start offset exceeds
max_end.
What the EG score is made of (scorer v4.0: the three questions the 0–10 score mixes, published apart · methodology)
The EG score (7.1): severity, escalated by confirmed exploitation. This CVE's 7.1 is its impact severity (EG Severity), not escalated.
- EG Severity
- 7.1 HIGHCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.GitHub Security Advisory CVSS
- EG Likelihood
- 0.2% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-10-26). FIRST's exploitation probability, not an EchelonGraph model.
- Confirmed exploitation
- None on record (CISA KEV, EG-KEV Tier 1)Reported apart from the likelihood: an observed fact, not a probability.
- EG Priority
- SSVC Track at medium mission impactTrack at low or medium mission impact; Track* at high (mission-essential systems).CISA BOD 26-04: 14 days if the affected system is publicly exposed; Fix on system upgrade if it is not.Each input and its source, and whom BOD 26-04 binds: the SSVC and BOD 26-04 blocks below.
SSVC (CISA's decision table, applied by EchelonGraph)Track at low or medium mission impact; Track* at high (mission-essential systems).
A fixed version is listed under Patch Availability. Apply it within your standard update timelines.
Exploitation none (no CISA value, KEV listing or exploit code on record) · Automatable no (CISA's BOD 26-04 default) · Technical impact total (CISA's BOD 26-04 default). EchelonGraph holds no SSVC assessment of this CVE from CISA: none of these inputs is from Vulnrichment. EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table
BOD 26-04 (CISA's remediation timeline, Table 1)14 days if the affected system is publicly exposed; Fix on system upgrade if it is not.
The score's inputs: In CISA KEV no (CISA's KEV catalog) · Automatable no (CISA's BOD 26-04 default) · Technical impact total (CISA's BOD 26-04 default). Where an input reads “CISA's BOD 26-04 default”, no one has published it for this CVE, and CISA's implementation guidance says: “If “Automatable” and “Technical Impact” information items about a CVE ID are not available and the CVE ID is not in the KEV Catalog, CISA will treat its values as “no” and “total,” respectively, until CISA or a third party provides metadata about the CVE ID. CISA will always provide the Vulnrichment data for a CVE ID listed in the KEV Catalog.” Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it