CVE-2021-47578

MEDIUMNVD 5.55.5

Also known asEUVD-2021-34580 (ENISA EUVD) · GHSA-7xj6-3ppc-gc3r (GitHub Security Advisories)Source: ENISA EUVD

5.5EG

EchelonGraph verdictMonitorRemediate within your standard update timelines (the SSVC decision on this page).

Lower severity and no public exploit yet

CISA-KEV: Not listedEPSS PROB: 0.2%CVSS: 5.5Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

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

CVSS v3: 5.5
EG Score: 5.5MEDIUMmedium confidence
EG Risk: 25
EPSS PROB: 0.2%
EPSS %ILE: 14th
KEV: Not listed

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 (model v2026.06.15, score date 2026-10-25). 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 every mission impact level.CISA BOD 26-04: 60 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 every mission impact level.

A fix is available. Apply it within your standard update timelines.

Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (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)60 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 Vulnrichment) · Technical impact partial (CISA Vulnrichment). 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

Published

June 19, 2024

Last Modified

November 21, 2024

References (3)

CVE Programhttps://git.kernel.org/stable/c/3344b58b53a76199dae48faa396e9fc37bf86992Patch
CVE Programhttps://git.kernel.org/stable/c/47d11d35203b0aa13533634e270fe2c3610e531bPatch
CVE Programhttps://git.kernel.org/stable/c/aa1f912712a109b6306746133de7e5343f016b26Patch

Affected Packages

(4 across 4 ecosystems)

Debian:11(1)

Package	Vulnerable range	Fix by version range	Dependents
linux	5.10.46-4 ... 5.10.92-1~bpo10+1 (6 versions)	every version up to 5.10.92-1: fixed in 5.10.92-1	—

Debian:12(1)

Package	Vulnerable range	Fix by version range	Dependents
linux	—	every version up to 5.15.15-1: fixed in 5.15.15-1	—

Debian:13(1)

Package	Vulnerable range	Fix by version range	Dependents
linux	—	every version up to 5.15.15-1: fixed in 5.15.15-1	—

Debian:14(1)

Package	Vulnerable range	Fix by version range	Dependents
linux	—	every version up to 5.15.15-1: fixed in 5.15.15-1	—

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

CWE-476NULL Pointer Dereference

Data Freshness Timeline

(refreshed 7× in last 7d / 37× in last 30d)

Each row is a time one of our pipelines fetched, updated or re-scored this CVE. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. An arrow marks a change the record states ("CVSS v3 → 9.1"); EPSS and GHSA rows show the values recorded at that time, not what changed (EPSS values are rounded; hover one for the exact figures). Most recent first.

Showing the most recent 97 of 206 refreshes on record for this CVE.

A repeat, a row identical to one the same pipeline wrote less than 10 seconds earlier, is not a separate refresh and is not counted. 3 repeat rows among the latest 100 are merged into the row they repeat. The 109 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

2026-11-02 16:38 UTCEPSS rescoreEPSS 0.2% · 14th percentile
2026-11-01 16:30 UTCEPSS rescoreEPSS 0.2% · 14th percentile
2026-10-31 16:29 UTCEPSS rescoreEPSS 0.2% · 14th percentile
2026-10-30 16:30 UTCEPSS rescoreEPSS 0.2% · 14th percentile
2026-10-29 16:29 UTCEPSS rescoreEPSS 0.2% · 14th percentile
2026-10-28 16:28 UTCEPSS rescoreEPSS 0.2% · 14th percentile
2026-10-27 16:28 UTCEPSS rescoreEPSS 0.2% · 14th percentile
2026-10-26 16:28 UTCEPSS rescoreEPSS 0.2% · 14th percentile
2026-10-25 18:18 UTCEG score recompute
2026-10-25 16:29 UTCEPSS rescoreEPSS 0.2% · 14th percentile
2026-10-24 21:41 UTCEG score recompute
2026-10-24 21:41 UTCGHSA enrichmentGHSA-7xj6-3ppc-gc3r · GitHub CVSS 5.5
2026-10-24 16:29 UTCEPSS rescoreEPSS 0.2% · 14th percentile
2026-10-23 16:28 UTCEPSS rescoreEPSS 0.2% · 14th percentile
2026-10-22 16:29 UTCEPSS rescoreEPSS 0.2% · 14th percentile
2026-10-21 16:28 UTCEPSS rescoreEPSS 0.2% · 14th percentile
2026-10-20 16:28 UTCEPSS rescoreEPSS 0.2% · 13th percentile
2026-10-19 16:28 UTCEPSS rescoreEPSS 0.2% · 13th percentile
2026-10-18 16:28 UTCEPSS rescoreEPSS 0.2% · 13th percentile
2026-10-18 08:49 UTCEG score recompute
2026-10-17 16:29 UTCEPSS rescoreEPSS 0.2% · 13th percentile
2026-10-16 16:34 UTCEPSS rescoreEPSS 0.2% · 13th percentile
2026-10-15 16:28 UTCEPSS rescoreEPSS 0.2% · 13th percentile
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2026-10-13 16:28 UTCEPSS rescoreEPSS 0.2% · 13th percentile

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2026-10-12 19:05 UTCEG score recompute
2026-10-12 16:30 UTCEPSS rescoreEPSS 0.2% · 13th percentile
2026-10-11 23:31 UTCEG score recompute
2026-10-11 13:44 UTCEPSS rescoreEPSS 0.2% · 13th percentile
2026-10-10 19:56 UTCEPSS rescoreEPSS 0.2% · 13th percentile
2026-10-10 16:03 UTCOSV refresh
2026-10-09 20:04 UTCEPSS rescoreEPSS 0.2% · 13th percentile
2026-10-08 16:40 UTCEPSS rescoreEPSS 0.2% · 13th percentile
2026-10-07 23:45 UTCEPSS rescoreEPSS 0.2% · 13th percentile
2026-10-06 15:14 UTCEPSS rescoreEPSS 0.2% · 13th percentile
2026-10-05 17:40 UTCEPSS rescoreEPSS 0.2% · 13th percentile
2026-10-04 23:19 UTCEPSS rescoreEPSS 0.2% · 13th percentile
2026-10-03 14:22 UTCEPSS rescoreEPSS 0.2% · 13th percentile
2026-10-02 16:23 UTCEPSS rescoreEPSS 0.2% · 13th percentile
2026-09-30 15:45 UTCEG score recompute
2026-09-30 15:00 UTCEPSS rescoreEPSS 0.2% · 13th percentile
2026-09-29 15:15 UTCEPSS rescoreEPSS 0.2% · 13th percentile
2026-09-28 13:47 UTCEPSS rescoreEPSS 0.2% · 13th percentile
2026-09-26 15:54 UTCEPSS rescoreEPSS 0.2% · 13th percentile
2026-09-26 00:21 UTCEPSS rescoreEPSS 0.2% · 13th percentile
2026-09-24 14:00 UTCEPSS rescoreEPSS 0.2% · 13th percentile
2026-09-23 13:45 UTCEPSS rescoreEPSS 0.2% · 15th percentile
2026-09-22 14:44 UTCEPSS rescoreEPSS 0.2% · 15th percentile
2026-09-21 20:28 UTCEPSS rescoreEPSS 0.2% · 15th percentile
2026-09-21 03:15 UTCOSV refresh
2026-09-20 20:13 UTCEPSS rescoreEPSS 0.2% · 15th percentile
2026-09-19 15:38 UTCEPSS rescoreEPSS 0.2% · 15th percentile
2026-09-18 19:24 UTCEPSS rescoreEPSS 0.2% · 15th percentile
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2026-09-16 14:05 UTCEPSS rescoreEPSS 0.2% · 15th percentile
2026-09-15 03:06 UTCEPSS rescoreEPSS 0.2% · 14th percentile
2026-09-12 14:57 UTCEPSS rescoreEPSS 0.2% · 14th percentile
2026-09-11 14:49 UTCEPSS rescoreEPSS 0.2% · 14th percentile
2026-09-11 09:33 UTCEPSS rescoreEPSS 0.2% · 14th percentile
2026-09-08 21:57 UTCEPSS rescoreEPSS 0.2% · 14th percentile
2026-09-07 15:58 UTCEPSS rescoreEPSS 0.2% · 14th percentile
2026-09-06 13:45 UTCEPSS rescoreEPSS 0.2% · 14th percentile
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2026-09-04 13:57 UTCEPSS rescoreEPSS 0.2% · 14th percentile
2026-09-04 05:03 UTCEPSS rescoreEPSS 0.2% · 14th percentile
2026-09-02 14:09 UTCEPSS rescoreEPSS 0.2% · 14th percentile
2026-09-02 01:10 UTCOSV refresh
2026-09-01 13:51 UTCEPSS rescoreEPSS 0.2% · 14th percentile
2026-08-30 19:14 UTCEPSS rescoreEPSS 0.2% · 14th percentile
2026-08-30 01:19 UTCEPSS rescoreEPSS 0.2% · 14th percentile
2026-08-28 21:38 UTCEPSS rescoreEPSS 0.2% · 14th percentile
2026-08-27 14:22 UTCEPSS rescoreEPSS 0.2% · 14th percentile
2026-08-26 14:43 UTCEPSS rescoreEPSS 0.2% · 14th percentile
2026-08-25 13:46 UTCEPSS rescoreEPSS 0.2% · 14th percentile
2026-08-24 14:13 UTCEPSS rescoreEPSS 0.2% · 14th percentile
2026-08-21 23:46 UTCEPSS rescoreEPSS 0.2% · 15th percentile
2026-08-20 22:52 UTCEPSS rescoreEPSS 0.2% · 15th percentile
2026-08-19 17:01 UTCEPSS rescoreEPSS 0.2% · 15th percentile
2026-08-18 13:45 UTCEPSS rescoreEPSS 0.2% · 15th percentile
2026-08-17 13:44 UTCEPSS rescoreEPSS 0.2% · 15th percentile
2026-08-16 14:53 UTCEPSS rescoreEPSS 0.2% · 15th percentile
2026-08-16 03:13 UTCOSV refresh
2026-08-16 02:11 UTCEPSS rescoreEPSS 0.2% · 15th percentile
2026-08-15 01:27 UTCEPSS rescoreEPSS 0.2% · 14th percentile
2026-08-13 21:57 UTCEPSS rescoreEPSS 0.2% · 14th percentile
2026-08-12 13:48 UTCEPSS rescoreEPSS 0.2% · 14th percentile
2026-08-11 13:38 UTCEPSS rescoreEPSS 0.2% · 14th percentile
2026-08-09 13:44 UTCEPSS rescoreEPSS 0.2% · 14th percentile
2026-08-08 16:34 UTCEPSS rescoreEPSS 0.2% · 14th percentile
2026-08-07 16:24 UTCEPSS rescoreEPSS 0.2% · 14th percentile
2026-08-06 13:44 UTCEPSS rescoreEPSS 0.2% · 14th percentile
2026-08-05 19:15 UTCEPSS rescoreEPSS 0.2% · 14th percentile
2026-08-04 15:06 UTCEPSS rescoreEPSS 0.2% · 14th percentile
2026-08-04 10:34 UTCEPSS rescoreEPSS 0.2% · 15th percentile
2026-08-03 10:33 UTCEPSS rescoreEPSS 0.2% · 15th percentile
2026-08-02 02:24 UTCEPSS rescoreEPSS 0.2% · 15th percentile
2026-08-01 04:13 UTCEPSS rescoreEPSS 0.2% · 15th percentile

Same CWE

10 shown

CWE-476

Frequently asked(5)

What is CVE-2021-47578?

CVE-2021-47578 is a medium-severity vulnerability; its CVE record was published on June 19, 2024. 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…

When was the CVE record for CVE-2021-47578 published?

The CVE record for CVE-2021-47578 was published on June 19, 2024. That is the record's publication date; the vulnerability itself may have been made public earlier. EchelonGraph's copy of the record carries a last-modified date of November 21, 2024; the record at its source may have been updated since.

Is CVE-2021-47578 actively exploited?

CVE-2021-47578 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.2% probability of exploitation in the next 30 days (14th percentile of EPSS-scored CVEs).

What is the CVSS score of CVE-2021-47578?

CVE-2021-47578 has a CVSS v3 base score of 5.5 (NVD).

How do I remediate CVE-2021-47578?

A fix for CVE-2021-47578 is available: update to the fixed version the vendor names in its advisory.

Dependency Blast Radius

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CVE-2021-47578

📅 Published

🔄 Last Modified

🔗 References (3)