scsi: core: Fix bad pointer dereference when ehandler kthread is invalid
In the Linux kernel, the following vulnerability has been resolved: scsi: core: Fix bad pointer dereference when ehandler kthread is invalid Commit 66a834d09293 ("scsi: core: Fix error handling of scsi_host_alloc()") changed the allocation logic to call put_device() to perform host cleanup with the assumption that IDA removal and stopping the kthread would properly be performed in scsi_host_dev_release(). However, in the unlikely case that the error handler thread fails to spawn, shost->ehandler is set to ERR_PTR(-ENOMEM). The error handler cleanup code in scsi_host_dev_release() will call kthread_stop() if shost->ehandler != NULL which will always be the case whether the kthread was successfully spawned or not. In the case that it failed to spawn this has the nasty side effect of trying to dereference an invalid pointer when kthread_stop() is called. The following splat provides an example of this behavior in the wild: scsi host11: error handler thread failed to spawn, error = -4 Kernel attempted to read user page (10c) - exploit attempt? (uid: 0) BUG: Kernel NULL pointer dereference on read at 0x0000010c Faulting instruction address: 0xc00000000818e9a8 Oops: Kernel access of bad area, sig: 11 [#1] LE PAGE_SIZE=64K MMU=Hash SMP NR_CPUS=2048 NUMA pSeries Modules linked in: ibmvscsi(+) scsi_transport_srp dm_multipath dm_mirror dm_region hash dm_log dm_mod fuse overlay squashfs loop CPU: 12 PID: 274 Comm: systemd-udevd Not tainted 5.13.0-rc7 #1 NIP: c00000000818e9a8 LR: c0000000089846e8 CTR: 0000000000007ee8 REGS: c000000037d12ea0 TRAP: 0300 Not tainted (5.13.0-rc7) MSR: 800000000280b033 <SF,VEC,VSX,EE,FP,ME,IR,DR,RI,LE> CR: 28228228 XER: 20040001 CFAR: c0000000089846e4 DAR: 000000000000010c DSISR: 40000000 IRQMASK: 0 GPR00: c0000000089846e8 c000000037d13140 c000000009cc1100 fffffffffffffffc GPR04: 0000000000000001 0000000000000000 0000000000000000 c000000037dc0000 GPR08: 0000000000000000 c000000037dc0000 0000000000000001 00000000fffff7ff GPR12: 0000000000008000 c00000000a049000 c000000037d13d00 000000011134d5a0 GPR16: 0000000000001740 c0080000190d0000 c0080000190d1740 c000000009129288 GPR20: c000000037d13bc0 0000000000000001 c000000037d13bc0 c0080000190b7898 GPR24: c0080000190b7708 0000000000000000 c000000033bb2c48 0000000000000000 GPR28: c000000046b28280 0000000000000000 000000000000010c fffffffffffffffc NIP [c00000000818e9a8] kthread_stop+0x38/0x230 LR [c0000000089846e8] scsi_host_dev_release+0x98/0x160 Call Trace: [c000000033bb2c48] 0xc000000033bb2c48 (unreliable) [c0000000089846e8] scsi_host_dev_release+0x98/0x160 [c00000000891e960] device_release+0x60/0x100 [c0000000087e55c4] kobject_release+0x84/0x210 [c00000000891ec78] put_device+0x28/0x40 [c000000008984ea4] scsi_host_alloc+0x314/0x430 [c0080000190b38bc] ibmvscsi_probe+0x54/0xad0 [ibmvscsi] [c000000008110104] vio_bus_probe+0xa4/0x4b0 [c00000000892a860] really_probe+0x140/0x680 [c00000000892aefc] driver_probe_device+0x15c/0x200 [c00000000892b63c] device_driver_attach+0xcc/0xe0 [c00000000892b740] __driver_attach+0xf0/0x200 [c000000008926f28] bus_for_each_dev+0xa8/0x130 [c000000008929ce4] driver_attach+0x34/0x50 [c000000008928fc0] bus_add_driver+0x1b0/0x300 [c00000000892c798] driver_register+0x98/0x1a0 [c00000000810eb60] __vio_register_driver+0x80/0xe0 [c0080000190b4a30] ibmvscsi_module_init+0x9c/0xdc [ibmvscsi] [c0000000080121d0] do_one_initcall+0x60/0x2d0 [c000000008261abc] do_init_module+0x7c/0x320 [c000000008265700] load_module+0x2350/0x25b0 [c000000008265cb4] __do_sys_finit_module+0xd4/0x160 [c000000008031110] system_call_exception+0x150/0x2d0 [c00000000800d35c] system_call_common+0xec/0x278 Fix this be nulling shost->ehandler when the kthread fails to spawn.
- Published
- May 21, 2024
- Updated
- Jun 17, 2026
- EPSS
- 0.2% · 14th percentile
- CWE
- CWE-476
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Report tools
Action score
22
Monitor
Low priority for now.
- CVSS
- 22 / 40 · 5.5 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 0 / 30 · 0.2%
CISA SSVC decision
- Exploitation
- none
- Automatable
- no
- Technical impact
- partial
Vulnrichment: CISA's decision-tree inputs.
Affected systems
| Vendor | Product | CPE |
|---|---|---|
| linux | linux kernel | cpe:2.3:o:linux:linux_kernel |
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- linux linux kernel4.9.273 and later · before 4.9.276
- linux linux kernel4.14.237 and later · before 4.14.240
- linux linux kernel4.19.195 and later · before 4.19.198
- linux linux kernel5.4.126 and later · before 5.4.134
- linux linux kernel5.10.44 and later · before 5.10.52
- linux linux kernel5.12.11 and later · before 5.12.19
- linux linux kernel5.13 and later · before 5.13.4
- linux linux kernel5.14
Versions reported by the vendor
Affected version ranges reported by the assigning authority (Linux). Independent of NVD's CPE analysis and usually ahead of it.
Linux Linux
- 5.13affected
- 8958181c1663e24a13434448e7d6b96b5d04900a and later · before d2f0b960d07e52bb664471b4de0ed8b08c636b3aaffected · git
- db08ce595dd64ea9859f7d088b51cbfc8e685c66 and later · before f3d0a109240c9bed5c60d819014786be3a2fe515affected · git
- 2dc85045ae65b9302a1d2e2ddd7ce4c030153a6a and later · before e1bd3fac2baa3d5c04375980c1d5263a3335af92affected · git
- 79296e292d67fa7b5fb8d8c27343683e823872c8 and later · before 887bfae2732b5b02a86a859fd239d34f7ff93c05affected · git
- 7a696ce1d5d16a33a6cd6400bbcc0339b2460e11 and later · before ea518b70ed5e4598c8d706f37fc16f7b06e440bdaffected · git
- 45d83db4728127944b237c0c8248987df9d478e7 and later · before 8e4212ecf0713dd57d0e3209a66201da582149b1affected · git
- 66a834d092930cf41d809c0e989b13cd6f9ca006 and later · before c1671d2d2ef8a84837eea1b4d99ca0c6a66fb691affected · git
- 66a834d092930cf41d809c0e989b13cd6f9ca006 and later · before 93aa71ad7379900e61c8adff6a710a4c18c7c99baffected · git
- 4.9.273 and later · before 4.9.276affected · semver
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| Debian:12 | linux | before 5.14.6-1 | 5.14.6-1 |
Same product
linux: all recordsOther highest-scoring records for the same primary product.
- CVE-2022-0847A flaw was found in the way the "flags" member of the new pipe buffer structure was lacking proper initialization in copy_page_to_iter_pipe KEV89Now
- CVE-2021-22555Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACEKEV85Now
- CVE-2016-5195Race condition in mm/gup.c in the Linux kernel 2.x through 4.x before 4.8.3 allows local users to gain privileges by leveraging incorrect haKEV83Now
- CVE-2019-13272In the Linux kernel before 5.1.17, ptrace_link in kernel/ptrace.c mishandles the recording of the credentials of a process that wants to creKEV77This week
- CVE-2013-6282The (1) get_user and (2) put_user API functions in the Linux kernel before 3.5.5 on the v6k and v7 ARM platforms do not validate certain addKEV77This week
- CVE-2013-2094The perf_swevent_init function in kernel/events/core.c in the Linux kernel before 3.8.9 uses an incorrect integer data type, which allows loKEV77This week
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
| Product / package | Fixed version | Source |
|---|---|---|
| Linux Linux | 4.14.240 | Vendor (CNA) |
| Linux Linux | 4.19.198 | Vendor (CNA) |
| Linux Linux | 4.9.276 | Vendor (CNA) |
| Linux Linux | 5.10.52 | Vendor (CNA) |
| Linux Linux | 5.12.19 | Vendor (CNA) |
| Linux Linux | 5.4.134 | Vendor (CNA) |
| Linux Linux | 887bfae2732b5b02a86a859fd239d34f7ff93c05 | Vendor (CNA) |
| Linux Linux | 8e4212ecf0713dd57d0e3209a66201da582149b1 | Vendor (CNA) |
| Linux Linux | 93aa71ad7379900e61c8adff6a710a4c18c7c99b | Vendor (CNA) |
| Linux Linux | c1671d2d2ef8a84837eea1b4d99ca0c6a66fb691 | Vendor (CNA) |
| Linux Linux | d2f0b960d07e52bb664471b4de0ed8b08c636b3a | Vendor (CNA) |
| Linux Linux | e1bd3fac2baa3d5c04375980c1d5263a3335af92 | Vendor (CNA) |
| Linux Linux | ea518b70ed5e4598c8d706f37fc16f7b06e440bd | Vendor (CNA) |
| Linux Linux | f3d0a109240c9bed5c60d819014786be3a2fe515 | Vendor (CNA) |
| debian:linux | 5.14.6-1 · Debian:12 | Package registry (OSV) |
Exploit status
No known public exploit
No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.
Research context
For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.
Timeline
From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.
No dated events beyond publication.
FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).
Patch and commit links
Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.
No commit or PR link among the references.
Credits
All researchersFinders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.
No credits in the CNA record.
Variant candidates
Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.
No nightly-computed relations.
Chain candidates
An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.
—
Bug bounty scope
No known public program.
Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).
Technical details
Attack conditions
- Someone with local access to the system can trigger it.
- A low-privileged account is enough.
- No user action is required.
- No special conditions are required; it is repeatable.
If successful
- Confidentiality
- none
- Integrity
- none
- Availability
- high · the service can be disrupted
- Attack vector
- Local
- Attack complexity
- Low
- Privileges required
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality impact
- None
- Integrity impact
- None
- Availability impact
- High
Weakness class (CWE)
CWE-476 · NULL Pointer DereferenceCVSS vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
nvd-primary
Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
MITRE has no CAPEC/ATT&CK mapping for this CWE.
Noroxi analysis
No Noroxi analysis for this record yet
We don't hand-write analysis for all 385,000+ vulnerabilities; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.
We use this product, ask for helpChange log
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
- git.kernel.org/stable/c/887bfae2732b5b02a86a859fd239d34f7ff93c05
- git.kernel.org/stable/c/8e4212ecf0713dd57d0e3209a66201da582149b1
- git.kernel.org/stable/c/93aa71ad7379900e61c8adff6a710a4c18c7c99b
- git.kernel.org/stable/c/c1671d2d2ef8a84837eea1b4d99ca0c6a66fb691
- git.kernel.org/stable/c/d2f0b960d07e52bb664471b4de0ed8b08c636b3a
- git.kernel.org/stable/c/e1bd3fac2baa3d5c04375980c1d5263a3335af92
- git.kernel.org/stable/c/ea518b70ed5e4598c8d706f37fc16f7b06e440bd
- git.kernel.org/stable/c/f3d0a109240c9bed5c60d819014786be3a2fe515
Vendor advisories and official records. Exploit/PoC links are deliberately left out.