In the Linux kernel, the following vulnerability has been resolved:
f2fs: prevent kernel warning due to negative i_nlink from corrupted image
WARNING: CPU: 1 PID: 9426 at fs/inode.c:417 drop_nlink+0xac/0xd0
home/cc/linux/fs/inode.c:417
Modules linked in:
CPU: 1 UID: 0 PID: 9426 Comm: syz-executor568 Not tainted
6.14.0-12627-g94d471a4f428 #2 PREEMPT(full)
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS
1.13.0-1ubuntu1.1 04/01/2014
RIP: 0010:drop_nlink+0xac/0xd0 home/cc/linux/fs/inode.c:417
Code: 48 8b 5d 28 be 08 00 00 00 48 8d bb 70 07 00 00 e8 f9 67 e6 ff
f0 48 ff 83 70 07 00 00 5b 5d e9 9a 12 82 ff e8 95 12 82 ff 90
<0f> 0b 90 c7 45 48 ff ff ff ff 5b 5d e9 83 12 82 ff e8 fe 5f e6
ff
RSP: 0018:ffffc900026b7c28 EFLAGS: 00010293
RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffffff8239710f
RDX: ffff888041345a00 RSI: ffffffff8239717b RDI: 0000000000000005
RBP: ffff888054509ad0 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000000 R11: ffffffff9ab36f08 R12: ffff88804bb40000
R13: ffff8880545091e0 R14: 0000000000008000 R15: ffff8880545091e0
FS: 000055555d0c5880(0000) GS:ffff8880eb3e3000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f915c55b178 CR3: 0000000050d20000 CR4: 0000000000352ef0
Call Trace:
f2fs_i_links_write home/cc/linux/fs/f2fs/f2fs.h:3194 [inline]
f2fs_drop_nlink+0xd1/0x3c0 home/cc/linux/fs/f2fs/dir.c:845
f2fs_delete_entry+0x542/0x1450 home/cc/linux/fs/f2fs/dir.c:909
f2fs_unlink+0x45c/0x890 home/cc/linux/fs/f2fs/namei.c:581
vfs_unlink+0x2fb/0x9b0 home/cc/linux/fs/namei.c:4544
do_unlinkat+0x4c5/0x6a0 home/cc/linux/fs/namei.c:4608
__do_sys_unlink home/cc/linux/fs/namei.c:4654 [inline]
__se_sys_unlink home/cc/linux/fs/namei.c:4652 [inline]
__x64_sys_unlink+0xc5/0x110 home/cc/linux/fs/namei.c:4652
do_syscall_x64 home/cc/linux/arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xc7/0x250 home/cc/linux/arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fb3d092324b
Code: 73 01 c3 48 c7 c1 c0 ff ff ff f7 d8 64 89 01 48 83 c8 ff c3 66
2e 0f 1f 84 00 00 00 00 00 90 f3 0f 1e fa b8 57 00 00 00 0f 05
<48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 c0 ff ff ff f7 d8 64 89 01
48
RSP: 002b:00007ffdc232d938 EFLAGS: 00000206 ORIG_RAX: 0000000000000057
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fb3d092324b
RDX: 00007ffdc232d960 RSI: 00007ffdc232d960 RDI: 00007ffdc232d9f0
RBP: 00007ffdc232d9f0 R08: 0000000000000001 R09: 00007ffdc232d7c0
R10: 00000000fffffffd R11: 0000000000000206 R12: 00007ffdc232eaf0
R13: 000055555d0cebb0 R14: 00007ffdc232d958 R15: 0000000000000001
What the EG score is made of (scorer v4.0: the three questions the 0–10 score mixes, published apart · methodology)
The EG score (5.5): severity, escalated by confirmed exploitation. This CVE's 5.5 is its impact severity (EG Severity), not escalated.
- EG Severity
- 5.5 MEDIUMCVSS-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. 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 fix is available. 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