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CVE-2021-47191· NVD / CVE Program· CNA Linux

scsi: scsi_debug: Fix out-of-bound read in resp_readcap16()

Noroxi assessment

Priority: Monitor (action score 28/100)

  • 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 3e20cb072679bdb47747ccc8bee3233a4cf0765a, 4e3ace0051e7e504b55d239daab8789dd89b863c, 5b8bed6464ad6653586e30df046185fd816ad999.
  • Mentioned 2 times in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to Linux Linux 3e20cb072679bdb47747ccc8bee3233a4cf0765a, 4e3ace0051e7e504b55d239daab8789dd89b863c, 5b8bed6464ad6653586e30df046185fd816ad999 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: Fix out-of-bound read in resp_readcap16() The following warning was observed running syzkaller: [ 3813.830724] sg_write: data in/out 65466/242 bytes for SCSI command 0x9e-- guessing data in; [ 3813.830724] program syz-executor not setting count and/or reply_len properly [ 3813.836956] ================================================================== [ 3813.839465] BUG: KASAN: stack-out-of-bounds in sg_copy_buffer+0x157/0x1e0 [ 3813.841773] Read of size 4096 at addr ffff8883cf80f540 by task syz-executor/1549 [ 3813.846612] Call Trace: [ 3813.846995] dump_stack+0x108/0x15f [ 3813.847524] print_address_description+0xa5/0x372 [ 3813.848243] kasan_report.cold+0x236/0x2a8 [ 3813.849439] check_memory_region+0x240/0x270 [ 3813.850094] memcpy+0x30/0x80 [ 3813.850553] sg_copy_buffer+0x157/0x1e0 [ 3813.853032] sg_copy_from_buffer+0x13/0x20 [ 3813.853660] fill_from_dev_buffer+0x135/0x370 [ 3813.854329] resp_readcap16+0x1ac/0x280 [ 3813.856917] schedule_resp+0x41f/0x1630 [ 3813.858203] scsi_debug_queuecommand+0xb32/0x17e0 [ 3813.862699] scsi_dispatch_cmd+0x330/0x950 [ 3813.863329] scsi_request_fn+0xd8e/0x1710 [ 3813.863946] __blk_run_queue+0x10b/0x230 [ 3813.864544] blk_execute_rq_nowait+0x1d8/0x400 [ 3813.865220] sg_common_write.isra.0+0xe61/0x2420 [ 3813.871637] sg_write+0x6c8/0xef0 [ 3813.878853] __vfs_write+0xe4/0x800 [ 3813.883487] vfs_write+0x17b/0x530 [ 3813.884008] ksys_write+0x103/0x270 [ 3813.886268] __x64_sys_write+0x77/0xc0 [ 3813.886841] do_syscall_64+0x106/0x360 [ 3813.887415] entry_SYSCALL_64_after_hwframe+0x44/0xa9 This issue can be reproduced with the following syzkaller log: r0 = openat(0xffffffffffffff9c, &(0x7f0000000040)='./file0\x00', 0x26e1, 0x0) r1 = syz_open_procfs(0xffffffffffffffff, &(0x7f0000000000)='fd/3\x00') open_by_handle_at(r1, &(0x7f00000003c0)=ANY=[@ANYRESHEX], 0x602000) r2 = syz_open_dev$sg(&(0x7f0000000000), 0x0, 0x40782) write$binfmt_aout(r2, &(0x7f0000000340)=ANY=[@ANYBLOB="00000000deff000000000000000000000000000000000000000000000000000047f007af9e107a41ec395f1bded7be24277a1501ff6196a83366f4e6362bc0ff2b247f68a972989b094b2da4fb3607fcf611a22dd04310d28c75039d"], 0x126) In resp_readcap16() we get "int alloc_len" value -1104926854, and then pass the huge arr_len to fill_from_dev_buffer(), but arr is only 32 bytes. This leads to OOB in sg_copy_buffer(). To solve this issue, define alloc_len as u32.

HighCVSS 7.1 · v3.1—No exploit Fix available
Published
Apr 10, 2024
Updated
Aug 5, 2026
EPSS
0.2% · 14th percentile

Report tools

JSON

Action score

28

Monitor

Low priority for now.

CVSS
28 / 40 · 7.1 / 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.

CNA vs NVD score

NVD
7.1
CNA · Linux
7.1
agree

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

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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 5.10.82
  • linux linux kernel5.11 and later · before 5.15.5

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

    • 2.6.18affected
    • c65b1445d153a66ca91b00c1f10187e495c17918 and later · before 3e20cb072679bdb47747ccc8bee3233a4cf0765aaffected · git
    • c65b1445d153a66ca91b00c1f10187e495c17918 and later · before 5b8bed6464ad6653586e30df046185fd816ad999affected · git
    • c65b1445d153a66ca91b00c1f10187e495c17918 and later · before 4e3ace0051e7e504b55d239daab8789dd89b863caffected · git
    • before 2.6.18not affected · semver
    • 5.10.82 and later · up to and including 5.10.*not affected · semver
    • 5.15.5 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 5.15.5-15.15.5-1
openSUSE:Leap 15.5dtb-aarch64before 5.14.21-150500.55.62.15.14.21-150500.55.62.1
openSUSE:Leap 15.5kernel-64kbbefore 5.14.21-150500.55.62.25.14.21-150500.55.62.2
openSUSE:Leap 15.5kernel-azurebefore 5.14.21-150500.33.51.15.14.21-150500.33.51.1
openSUSE:Leap 15.5kernel-debugbefore 5.14.21-150500.55.62.25.14.21-150500.55.62.2
openSUSE:Leap 15.5kernel-defaultbefore 5.14.21-150500.55.62.25.14.21-150500.55.62.2
openSUSE:Leap 15.5kernel-default-basebefore 5.14.21-150500.55.62.2.150500.6.27.25.14.21-150500.55.62.2.150500.6.27.2
openSUSE:Leap 15.5kernel-docsbefore 5.14.21-150500.55.62.25.14.21-150500.55.62.2
openSUSE:Leap 15.5kernel-kvmsmallbefore 5.14.21-150500.55.62.25.14.21-150500.55.62.2
openSUSE:Leap 15.5kernel-obs-buildbefore 5.14.21-150500.55.62.25.14.21-150500.55.62.2
openSUSE:Leap 15.5kernel-obs-qabefore 5.14.21-150500.55.62.15.14.21-150500.55.62.1
openSUSE:Leap 15.5kernel-rtbefore 5.14.21-150500.13.52.15.14.21-150500.13.52.1
openSUSE:Leap 15.5kernel-rt_debugbefore 5.14.21-150500.13.52.15.14.21-150500.13.52.1
openSUSE:Leap 15.5kernel-sourcebefore 5.14.21-150500.55.62.25.14.21-150500.55.62.2
openSUSE:Leap 15.5kernel-source-azurebefore 5.14.21-150500.33.51.15.14.21-150500.33.51.1
openSUSE:Leap 15.5kernel-source-rtbefore 5.14.21-150500.13.52.15.14.21-150500.13.52.1
openSUSE:Leap 15.5kernel-symsbefore 5.14.21-150500.55.62.15.14.21-150500.55.62.1
openSUSE:Leap 15.5kernel-syms-azurebefore 5.14.21-150500.33.51.15.14.21-150500.33.51.1
openSUSE:Leap 15.5kernel-syms-rtbefore 5.14.21-150500.13.52.15.14.21-150500.13.52.1
openSUSE:Leap 15.5kernel-zfcpdumpbefore 5.14.21-150500.55.62.25.14.21-150500.55.62.2
openSUSE:Leap Micro 5.3kernel-defaultbefore 5.14.21-150400.24.119.15.14.21-150400.24.119.1
openSUSE:Leap Micro 5.3kernel-default-basebefore 5.14.21-150400.24.119.1.150400.24.56.15.14.21-150400.24.119.1.150400.24.56.1
openSUSE:Leap Micro 5.3kernel-rtbefore 5.14.21-150400.15.79.15.14.21-150400.15.79.1
SUSE:Linux Enterprise High Availability Extension 12 SP5kernel-defaultbefore 4.12.14-122.225.14.12.14-122.225.1

+49

Same product

linux: all records

Other 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 KEV
    89Now
  • CVE-2021-22555Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACEKEV
    85Now
  • 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 haKEV
    83Now

Published before and after this one in the same product

  • ← EarlierCVE-2021-47189Apr 10, 2024 · btrfs: fix memory ordering between normal and ordered work functions
    31Monitor
  • ← EarlierCVE-2021-47190Apr 10, 2024 · perf bpf: Avoid memory leak from perf_env__insert_btf()
    22Monitor
  • Later →CVE-2021-47192Apr 10, 2024 · scsi: core: sysfs: Fix hang when device state is set via sysfs
    21Monitor

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 Linux3e20cb072679bdb47747ccc8bee3233a4cf0765aVendor (CNA)
Linux Linux4e3ace0051e7e504b55d239daab8789dd89b863cVendor (CNA)
Linux Linux5b8bed6464ad6653586e30df046185fd816ad999Vendor (CNA)
debian:linux5.15.5-1 · Debian:12Package registry (OSV)
opensuse:dtb-aarch645.14.21-150500.55.62.1 · openSUSE:Leap 15.5Package registry (OSV)
opensuse:kernel-64kb5.14.21-150500.55.62.2 · openSUSE:Leap 15.5Package registry (OSV)
opensuse:kernel-azure5.14.21-150500.33.51.1 · openSUSE:Leap 15.5Package registry (OSV)
opensuse:kernel-debug5.14.21-150500.55.62.2 · openSUSE:Leap 15.5Package registry (OSV)
opensuse:kernel-default5.14.21-150400.24.119.1 · openSUSE:Leap Micro 5.3Package registry (OSV)
opensuse:kernel-default-base5.14.21-150400.24.119.1.150400.24.56.1 · openSUSE:Leap Micro 5.3Package registry (OSV)
opensuse:kernel-docs5.14.21-150500.55.62.2 · openSUSE:Leap 15.5Package registry (OSV)
opensuse:kernel-kvmsmall5.14.21-150500.55.62.2 · openSUSE:Leap 15.5Package registry (OSV)
opensuse:kernel-obs-build5.14.21-150500.55.62.2 · openSUSE:Leap 15.5Package registry (OSV)
opensuse:kernel-rt5.14.21-150400.15.79.1 · openSUSE:Leap Micro 5.3Package registry (OSV)
opensuse:kernel-source-azure5.14.21-150500.33.51.1 · openSUSE:Leap 15.5Package registry (OSV)
opensuse:kernel-syms-azure5.14.21-150500.33.51.1 · openSUSE:Leap 15.5Package registry (OSV)
suse:kernel-64kb5.14.21-150400.24.119.1 · SUSE:Linux Enterprise High Performance Computing 15 SP4-ESPOSPackage registry (OSV)
suse:kernel-azure5.14.21-150500.33.51.1 · SUSE:Linux Enterprise Module for Public Cloud 15 SP5Package registry (OSV)
suse:kernel-default5.14.21-150400.24.119.1 · SUSE:Linux Enterprise Micro 5.3Package registry (OSV)
suse:kernel-default-base5.14.21-150400.24.119.1.150400.24.56.1 · SUSE:Linux Enterprise Micro 5.3Package registry (OSV)
suse:kernel-docs5.14.21-150400.24.119.1 · SUSE:Linux Enterprise High Performance Computing 15 SP4-ESPOSPackage registry (OSV)
suse:kernel-livepatch-SLE15-SP4_Update_261-150400.9.3.1 · SUSE:Linux Enterprise Live Patching 15 SP4Package registry (OSV)
suse:kernel-obs-build5.14.21-150400.24.119.1 · SUSE:Linux Enterprise High Performance Computing 15 SP4-ESPOSPackage registry (OSV)
suse:kernel-source5.14.21-150400.24.119.1 · SUSE:Linux Enterprise High Performance Computing 15 SP4-ESPOSPackage registry (OSV)
suse:kernel-source-azure5.14.21-150500.33.51.1 · SUSE:Linux Enterprise Module for Public Cloud 15 SP5Package registry (OSV)
suse:kernel-syms5.14.21-150400.24.119.1 · SUSE:Linux Enterprise High Performance Computing 15 SP4-ESPOSPackage registry (OSV)
suse:kernel-syms-azure5.14.21-150500.33.51.1 · SUSE:Linux Enterprise Module for Public Cloud 15 SP5Package registry (OSV)
suse:kernel-zfcpdump5.14.21-150400.24.119.1 · SUSE:Linux Enterprise Server 15 SP4-LTSSPackage 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.

EPSS, last 120 days

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 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
high · data can be read
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
High
Integrity impact
None
Availability impact
High

Weakness class (CWE)

CWE-125 · Out-of-bounds Read

CVSS vector

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/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.

ATT&CK techniques

—

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