CVE-2021-47337

MEDIUMNVD 5.55.5

Also known asEUVD-2021-34342 (ENISA EUVD) · GHSA-5vvx-6299-h82w (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: 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.

CVSS v3: 5.5
EG Score: 5.5MEDIUMmedium confidence
EG Risk: 25
EPSS PROB: 0.2%
EPSS %ILE: 15th
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

May 21, 2024

Last Modified

December 24, 2024

References (8)

CVE Programhttps://git.kernel.org/stable/c/887bfae2732b5b02a86a859fd239d34f7ff93c05Patch
CVE Programhttps://git.kernel.org/stable/c/8e4212ecf0713dd57d0e3209a66201da582149b1Patch
CVE Programhttps://git.kernel.org/stable/c/93aa71ad7379900e61c8adff6a710a4c18c7c99bPatch
CVE Programhttps://git.kernel.org/stable/c/c1671d2d2ef8a84837eea1b4d99ca0c6a66fb691Patch
CVE Programhttps://git.kernel.org/stable/c/d2f0b960d07e52bb664471b4de0ed8b08c636b3aPatch
CVE Programhttps://git.kernel.org/stable/c/e1bd3fac2baa3d5c04375980c1d5263a3335af92Patch
CVE Programhttps://git.kernel.org/stable/c/ea518b70ed5e4598c8d706f37fc16f7b06e440bdPatch
CVE Programhttps://git.kernel.org/stable/c/f3d0a109240c9bed5c60d819014786be3a2fe515Patch

Affected Packages

(4 across 4 ecosystems)

Debian:11(1)

Package	Vulnerable range	Fix by version range	Dependents
linux	5.10.46-4, 5.10.46-5, 5.10.70-1~bpo10+1	every version up to 5.10.70-1: fixed in 5.10.70-1	—

Debian:12(1)

Package	Vulnerable range	Fix by version range	Dependents
linux	—	every version up to 5.14.6-1: fixed in 5.14.6-1	—

Debian:13(1)

Package	Vulnerable range	Fix by version range	Dependents
linux	—	every version up to 5.14.6-1: fixed in 5.14.6-1	—

Debian:14(1)

Package	Vulnerable range	Fix by version range	Dependents
linux	—	every version up to 5.14.6-1: fixed in 5.14.6-1	—

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 207 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 110 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% · 15th percentile
2026-11-01 16:30 UTCEPSS rescoreEPSS 0.2% · 15th percentile
2026-10-31 16:29 UTCEPSS rescoreEPSS 0.2% · 15th percentile
2026-10-30 16:30 UTCEPSS rescoreEPSS 0.2% · 15th percentile
2026-10-29 16:29 UTCEPSS rescoreEPSS 0.2% · 15th percentile
2026-10-28 16:28 UTCEPSS rescoreEPSS 0.2% · 15th 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 21:45 UTCEG score recompute
2026-10-24 21:45 UTCGHSA enrichmentGHSA-5vvx-6299-h82w · 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
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2026-10-18 16:28 UTCEPSS rescoreEPSS 0.2% · 14th percentile
2026-10-18 08:49 UTCEG score recompute
2026-10-17 16:29 UTCEPSS rescoreEPSS 0.2% · 14th percentile
2026-10-16 16:34 UTCEPSS rescoreEPSS 0.2% · 14th percentile
2026-10-15 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
2026-10-09 22:55 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
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2026-10-04 23:19 UTCEPSS rescoreEPSS 0.2% · 13th percentile
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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
2026-09-20 20:13 UTCEPSS rescoreEPSS 0.2% · 15th percentile
2026-09-20 07:13 UTCOSV refresh
2026-09-19 15:38 UTCEPSS rescoreEPSS 0.2% · 15th percentile
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2026-09-12 14:57 UTCEPSS rescoreEPSS 0.2% · 15th percentile
2026-09-11 14:49 UTCEPSS rescoreEPSS 0.2% · 15th percentile
2026-09-11 09:33 UTCEPSS rescoreEPSS 0.2% · 15th percentile
2026-09-08 21:57 UTCEPSS rescoreEPSS 0.2% · 14th percentile
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2026-09-02 14:09 UTCEPSS rescoreEPSS 0.2% · 14th percentile
2026-09-01 13:51 UTCEPSS rescoreEPSS 0.2% · 14th percentile
2026-09-01 10:29 UTCOSV refresh
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
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2026-08-21 23:46 UTCEPSS rescoreEPSS 0.2% · 15th percentile
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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 02:11 UTCEPSS rescoreEPSS 0.2% · 15th percentile
2026-08-15 09:37 UTCOSV refresh
2026-08-15 01:27 UTCEPSS rescoreEPSS 0.2% · 15th percentile
2026-08-13 21:57 UTCEPSS rescoreEPSS 0.2% · 15th percentile
2026-08-12 13:48 UTCEPSS rescoreEPSS 0.2% · 15th percentile
2026-08-11 13:38 UTCEPSS rescoreEPSS 0.2% · 15th percentile
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2026-08-07 16:24 UTCEPSS rescoreEPSS 0.2% · 15th percentile
2026-08-06 13:44 UTCEPSS rescoreEPSS 0.2% · 15th percentile
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2026-08-04 15:06 UTCEPSS rescoreEPSS 0.2% · 15th percentile
2026-08-04 10:34 UTCEPSS rescoreEPSS 0.2% · 15th percentile
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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-2021-47337?

CVE-2021-47337 is a medium-severity vulnerability; its CVE record was published on May 21, 2024. 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…

When was the CVE record for CVE-2021-47337 published?

The CVE record for CVE-2021-47337 was published on May 21, 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 December 24, 2024; the record at its source may have been updated since.

Is CVE-2021-47337 actively exploited?

CVE-2021-47337 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.2% probability of exploitation in the next 30 days (15th percentile of EPSS-scored CVEs).

What is the CVSS score of CVE-2021-47337?

CVE-2021-47337 has a CVSS v3 base score of 5.5 (NVD).

How do I remediate CVE-2021-47337?

A fix for CVE-2021-47337 is available: update to the fixed version the vendor names in its advisory.

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CVE-2021-47337

📅 Published

🔄 Last Modified

🔗 References (8)