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NVD / CVE Program· CNA Linux

CVE-2021-47578: scsi: scsi_debug: Don't call kcalloc() if size arg is zero

Noroxi assessment

Priority: Monitor (action score 22/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.23% (FIRST EPSS).
  • 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.
  • Fixed version: Linux Linux 3344b58b53a76199dae48faa396e9fc37bf86992, 47d11d35203b0aa13533634e270fe2c3610e531b, aa1f912712a109b6306746133de7e5343f016b26.
  • Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to Linux Linux 3344b58b53a76199dae48faa396e9fc37bf86992, 47d11d35203b0aa13533634e270fe2c3610e531b, aa1f912712a109b6306746133de7e5343f016b26 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

In the Linux kernel, the following vulnerability has been resolved: scsi: scsi_debug: Don't call kcalloc() if size arg is zero If the size arg to kcalloc() is zero, it returns ZERO_SIZE_PTR. Because of that, for a following NULL pointer check to work on the returned pointer, kcalloc() must not be called with the size arg equal to zero. Return early without error before the kcalloc() call if size arg is zero. BUG: KASAN: null-ptr-deref in memcpy include/linux/fortify-string.h:191 [inline] BUG: KASAN: null-ptr-deref in sg_copy_buffer+0x138/0x240 lib/scatterlist.c:974 Write of size 4 at addr 0000000000000010 by task syz-executor.1/22789 CPU: 1 PID: 22789 Comm: syz-executor.1 Not tainted 5.15.0-syzk #1 Hardware name: Red Hat KVM, BIOS 1.13.0-2 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x89/0xb5 lib/dump_stack.c:106 __kasan_report mm/kasan/report.c:446 [inline] kasan_report.cold.14+0x112/0x117 mm/kasan/report.c:459 check_region_inline mm/kasan/generic.c:183 [inline] kasan_check_range+0x1a3/0x210 mm/kasan/generic.c:189 memcpy+0x3b/0x60 mm/kasan/shadow.c:66 memcpy include/linux/fortify-string.h:191 [inline] sg_copy_buffer+0x138/0x240 lib/scatterlist.c:974 do_dout_fetch drivers/scsi/scsi_debug.c:2954 [inline] do_dout_fetch drivers/scsi/scsi_debug.c:2946 [inline] resp_verify+0x49e/0x930 drivers/scsi/scsi_debug.c:4276 schedule_resp+0x4d8/0x1a70 drivers/scsi/scsi_debug.c:5478 scsi_debug_queuecommand+0x8c9/0x1ec0 drivers/scsi/scsi_debug.c:7533 scsi_dispatch_cmd drivers/scsi/scsi_lib.c:1520 [inline] scsi_queue_rq+0x16b0/0x2d40 drivers/scsi/scsi_lib.c:1699 blk_mq_dispatch_rq_list+0xb9b/0x2700 block/blk-mq.c:1639 __blk_mq_sched_dispatch_requests+0x28f/0x590 block/blk-mq-sched.c:325 blk_mq_sched_dispatch_requests+0x105/0x190 block/blk-mq-sched.c:358 __blk_mq_run_hw_queue+0xe5/0x150 block/blk-mq.c:1761 __blk_mq_delay_run_hw_queue+0x4f8/0x5c0 block/blk-mq.c:1838 blk_mq_run_hw_queue+0x18d/0x350 block/blk-mq.c:1891 blk_mq_sched_insert_request+0x3db/0x4e0 block/blk-mq-sched.c:474 blk_execute_rq_nowait+0x16b/0x1c0 block/blk-exec.c:62 blk_execute_rq+0xdb/0x360 block/blk-exec.c:102 sg_scsi_ioctl drivers/scsi/scsi_ioctl.c:621 [inline] scsi_ioctl+0x8bb/0x15c0 drivers/scsi/scsi_ioctl.c:930 sg_ioctl_common+0x172d/0x2710 drivers/scsi/sg.c:1112 sg_ioctl+0xa2/0x180 drivers/scsi/sg.c:1165 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:874 [inline] __se_sys_ioctl fs/ioctl.c:860 [inline] __x64_sys_ioctl+0x19d/0x220 fs/ioctl.c:860 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3a/0x80 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae

MediumCVSS 5.5 · v3.1—No exploit Fix available
Published
Jun 19, 2024
Updated
Jun 17, 2026
EPSS
0.2% · 14th percentile

Report tools

JSON

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.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

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  • when exploit code appears or is weaponized
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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
linuxlinux kernel

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • linux linux kernelbefore 5.10.88
  • linux linux kernel5.11 and later · before 5.15.11

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

    • 5.8affected
    • c3e2fe9222d428f115baeba2f6b3637b3aa444cd and later · before aa1f912712a109b6306746133de7e5343f016b26affected · git
    • c3e2fe9222d428f115baeba2f6b3637b3aa444cd and later · before 47d11d35203b0aa13533634e270fe2c3610e531baffected · git
    • c3e2fe9222d428f115baeba2f6b3637b3aa444cd and later · before 3344b58b53a76199dae48faa396e9fc37bf86992affected · git
    • before 5.8not affected · semver
    • 5.10.88 and later · up to and including 5.10.*not affected · semver
    • 5.15.11 and later · up to and including 5.15.*not affected · semver
    • 5.16 and laternot affected · original_commit_for_fix

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:12linuxbefore 5.15.15-15.15.15-1
openSUSE:Leap 15.5dtb-aarch64before 5.14.21-150500.55.73.15.14.21-150500.55.73.1
openSUSE:Leap 15.5kernel-64kbbefore 5.14.21-150500.55.73.15.14.21-150500.55.73.1
openSUSE:Leap 15.5kernel-azurebefore 5.14.21-150500.33.60.15.14.21-150500.33.60.1
openSUSE:Leap 15.5kernel-debugbefore 5.14.21-150500.55.73.15.14.21-150500.55.73.1
openSUSE:Leap 15.5kernel-docsbefore 5.14.21-150500.55.73.25.14.21-150500.55.73.2
openSUSE:Leap 15.5kernel-kvmsmallbefore 5.14.21-150500.55.73.15.14.21-150500.55.73.1
openSUSE:Leap 15.5kernel-obs-buildbefore 5.14.21-150500.55.73.15.14.21-150500.55.73.1
openSUSE:Leap 15.5kernel-obs-qabefore 5.14.21-150500.55.73.15.14.21-150500.55.73.1
openSUSE:Leap 15.5kernel-rtbefore 5.14.21-150500.13.61.15.14.21-150500.13.61.1
openSUSE:Leap 15.5kernel-rt_debugbefore 5.14.21-150500.13.61.15.14.21-150500.13.61.1
openSUSE:Leap 15.5kernel-sourcebefore 5.14.21-150500.55.73.15.14.21-150500.55.73.1
openSUSE:Leap 15.5kernel-source-azurebefore 5.14.21-150500.33.60.15.14.21-150500.33.60.1
openSUSE:Leap 15.5kernel-source-rtbefore 5.14.21-150500.13.61.15.14.21-150500.13.61.1
openSUSE:Leap 15.5kernel-symsbefore 5.14.21-150500.55.73.15.14.21-150500.55.73.1
openSUSE:Leap 15.5kernel-syms-azurebefore 5.14.21-150500.33.60.15.14.21-150500.33.60.1
openSUSE:Leap 15.5kernel-syms-rtbefore 5.14.21-150500.13.61.15.14.21-150500.13.61.1
openSUSE:Leap 15.5kernel-zfcpdumpbefore 5.14.21-150500.55.73.15.14.21-150500.55.73.1
openSUSE:Leap Micro 5.5kernel-defaultbefore 5.14.21-150500.55.73.15.14.21-150500.55.73.1
openSUSE:Leap Micro 5.5kernel-default-basebefore 5.14.21-150500.55.73.1.150500.6.33.85.14.21-150500.55.73.1.150500.6.33.8
SUSE:Linux Enterprise High Performance Computing 15 SP4-ESPOSkernel-64kbbefore 5.14.21-150400.24.128.15.14.21-150400.24.128.1
SUSE:Linux Enterprise High Performance Computing 15 SP4-ESPOSkernel-docsbefore 5.14.21-150400.24.128.15.14.21-150400.24.128.1
SUSE:Linux Enterprise High Performance Computing 15 SP4-ESPOSkernel-obs-buildbefore 5.14.21-150400.24.128.15.14.21-150400.24.128.1
SUSE:Linux Enterprise High Performance Computing 15 SP4-ESPOSkernel-sourcebefore 5.14.21-150400.24.128.15.14.21-150400.24.128.1

+24

Same product

linux: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-31431crypto: algif_aead - Revert to operating out-of-placeKEV
    90Now
  • 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 KEV
    89Now
  • CVE-2021-22555Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACEKEV
    85Now

Published before and after this one in the same product

  • ← EarlierCVE-2021-47576Jun 19, 2024 · scsi: scsi_debug: Sanity check block descriptor length in resp_mode_select()
    31Monitor
  • ← EarlierCVE-2021-47577Jun 19, 2024 · io-wq: check for wq exit after adding new worker task_work
    18Monitor
  • Later →CVE-2021-47579Jun 19, 2024 · ovl: fix warning in ovl_create_real()
    22Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Linux Linux3344b58b53a76199dae48faa396e9fc37bf86992Vendor (CNA)
Linux Linux47d11d35203b0aa13533634e270fe2c3610e531bVendor (CNA)
Linux Linuxaa1f912712a109b6306746133de7e5343f016b26Vendor (CNA)
debian:linux5.15.15-1 · Debian:12Package registry (OSV)
opensuse:dtb-aarch645.14.21-150500.55.73.1 · openSUSE:Leap 15.5Package registry (OSV)
opensuse:kernel-64kb5.14.21-150500.55.73.1 · openSUSE:Leap 15.5Package registry (OSV)
opensuse:kernel-azure5.14.21-150500.33.60.1 · openSUSE:Leap 15.5Package registry (OSV)
opensuse:kernel-debug5.14.21-150500.55.73.1 · openSUSE:Leap 15.5Package registry (OSV)
opensuse:kernel-default5.14.21-150500.55.73.1 · openSUSE:Leap Micro 5.5Package registry (OSV)
opensuse:kernel-default-base5.14.21-150500.55.73.1.150500.6.33.8 · openSUSE:Leap Micro 5.5Package registry (OSV)
opensuse:kernel-rt5.14.21-150500.13.61.1 · openSUSE:Leap 15.5Package registry (OSV)
opensuse:kernel-rt_debug5.14.21-150500.13.61.1 · openSUSE:Leap 15.5Package registry (OSV)
opensuse:kernel-source-azure5.14.21-150500.33.60.1 · openSUSE:Leap 15.5Package registry (OSV)
opensuse:kernel-source-rt5.14.21-150500.13.61.1 · openSUSE:Leap 15.5Package registry (OSV)
opensuse:kernel-syms-azure5.14.21-150500.33.60.1 · openSUSE:Leap 15.5Package registry (OSV)
opensuse:kernel-syms-rt5.14.21-150500.13.61.1 · openSUSE:Leap 15.5Package registry (OSV)
suse:kernel-64kb5.14.21-150400.24.128.1 · SUSE:Linux Enterprise High Performance Computing 15 SP4-ESPOSPackage registry (OSV)
suse:kernel-azure5.14.21-150500.33.60.1 · SUSE:Linux Enterprise Module for Public Cloud 15 SP5Package registry (OSV)
suse:kernel-default5.14.21-150400.24.128.1 · SUSE:Linux Enterprise Micro 5.3Package registry (OSV)
suse:kernel-default-base5.14.21-150400.24.128.1.150400.24.62.1 · SUSE:Linux Enterprise Micro 5.3Package registry (OSV)
suse:kernel-livepatch-SLE15-SP4_Update_291-150400.9.3.1 · SUSE:Linux Enterprise Live Patching 15 SP4Package registry (OSV)
suse:kernel-livepatch-SLE15-SP5-RT_Update_171-150500.11.3.1 · SUSE:Linux Enterprise Live Patching 15 SP5Package registry (OSV)
suse:kernel-rt5.14.21-150500.13.61.1 · SUSE:Linux Enterprise Micro 5.5Package registry (OSV)
suse:kernel-rt_debug5.14.21-150500.13.61.1 · SUSE:Real Time Module 15 SP5Package registry (OSV)
suse:kernel-source-azure5.14.21-150500.33.60.1 · SUSE:Linux Enterprise Module for Public Cloud 15 SP5Package registry (OSV)
suse:kernel-source-rt5.14.21-150500.13.61.1 · SUSE:Linux Enterprise Micro 5.5Package registry (OSV)
suse:kernel-syms-azure5.14.21-150500.33.60.1 · SUSE:Linux Enterprise Module for Public Cloud 15 SP5Package registry (OSV)
suse:kernel-syms-rt5.14.21-150500.13.61.1 · SUSE:Real Time Module 15 SP5Package 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.

No history yet (it accumulates with the daily EPSS job).

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 researchers

Finders, 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).

National notice (Türkiye Cybersecurity Directorate / USOM)

Official security notices citing this record; remediation advice is on the agency's page.

All national notices →

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 Dereference

CVSS 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.

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (2 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records