In the Linux kernel, the following vulnerability has been resolved:
AppArmor: Allow apparmor to handle unaligned dfa tables
The dfa tables can originate from kernel or userspace and 8-byte alignment
isn't always guaranteed and as such may trigger unaligned memory accesses
on various architectures. Resulting in the following
[ 73.901376] WARNING: CPU: 0 PID: 341 at security/apparmor/match.c:316 aa_dfa_unpack+0x6cc/0x720
[ 74.015867] Modules linked in: binfmt_misc evdev flash sg drm drm_panel_orientation_quirks backlight i2c_core configfs nfnetlink autofs4 ext4 crc16 mbcache jbd2 hid_generic usbhid sr_mod hid cdrom
sd_mod ata_generic ohci_pci ehci_pci ehci_hcd ohci_hcd pata_ali libata sym53c8xx scsi_transport_spi tg3 scsi_mod usbcore libphy scsi_common mdio_bus usb_common
[ 74.428977] CPU: 0 UID: 0 PID: 341 Comm: apparmor_parser Not tainted 6.18.0-rc6+ #9 NONE
[ 74.536543] Call Trace:
[ 74.568561] [<0000000000434c24>] dump_stack+0x8/0x18
[ 74.633757] [<0000000000476438>] __warn+0xd8/0x100
[ 74.696664] [<00000000004296d4>] warn_slowpath_fmt+0x34/0x74
[ 74.771006] [<00000000008db28c>] aa_dfa_unpack+0x6cc/0x720
[ 74.843062] [<00000000008e643c>] unpack_pdb+0xbc/0x7e0
[ 74.910545] [<00000000008e7740>] unpack_profile+0xbe0/0x1300
[ 74.984888] [<00000000008e82e0>] aa_unpack+0xe0/0x6a0
[ 75.051226] [<00000000008e3ec4>] aa_replace_profiles+0x64/0x1160
[ 75.130144] [<00000000008d4d90>] policy_update+0xf0/0x280
[ 75.201057] [<00000000008d4fc8>] profile_replace+0xa8/0x100
[ 75.274258] [<0000000000766bd0>] vfs_write+0x90/0x420
[ 75.340594] [<00000000007670cc>] ksys_write+0x4c/0xe0
[ 75.406932] [<0000000000767174>] sys_write+0x14/0x40
[ 75.472126] [<0000000000406174>] linux_sparc_syscall+0x34/0x44
[ 75.548802] ---[ end trace 0000000000000000 ]---
[ 75.609503] dfa blob stream 0xfff0000008926b96 not aligned.
[ 75.682695] Kernel unaligned access at TPC[8db2a8] aa_dfa_unpack+0x6e8/0x720
Work around it by using the get_unaligned_xx() helpers.
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