NVD / CVE Program· CNA Linux

CVE-2021-47328: scsi: iscsi: Fix conn use after free during resets

Noroxi assessment

Priority: Monitor (action score 31/100)

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: 0.76% (FIRST EPSS); higher than 55.7% of all records.
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 3.19, 3.3, 3.5.
Severity is disputed: the assigning authority (CNA) scores it 9.8, NVD 7.8.
Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to Linux Linux 3.19, 3.3, 3.5 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: iscsi: Fix conn use after free during resets If we haven't done a unbind target call we can race where iscsi_conn_teardown wakes up the EH thread and then frees the conn while those threads are still accessing the conn ehwait. We can only do one TMF per session so this just moves the TMF fields from the conn to the session. We can then rely on the iscsi_session_teardown->iscsi_remove_session->__iscsi_unbind_session call to remove the target and it's devices, and know after that point there is no device or scsi-ml callout trying to access the session.

HighCVSS 7.8 · v3.1—No exploit Fix available

Memory safety

Published: May 21, 2024
Updated: Aug 5, 2026
EPSS: 0.7% · 55th percentile
CWE: CWE-416

Report tools

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Action score

Monitor

Low priority for now.

CVSS: 31 / 40 · 7.8 / 10
CISA KEV: 0 / 30 · Not listed
EPSS: 0 / 30 · 0.7%

CISA SSVC decision

Exploitation: none
Automatable: no
Technical impact: partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD: 7.8
CNA · Linux: 9.8; 2.0 point gap

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

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

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

If any of these changes, we'll tell you in the daily email digest.

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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.

ProductVersion

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 kernelbefore 4.19.198
linux linux kernel4.20 and later · before 5.4.134
linux linux kernel5.5 and later · before 5.10.52
linux linux kernel5.11 and later · before 5.12.19
linux linux kernel5.13 and later · before 5.13.4

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
- 861a9633c22ee8b484e1b4054995f7e1b94a3834, 0adcec66bce9b7e84847da09ae3f8bc36e753312, 20b38ab5b687df3dbb873cfb0efa946a021f890a, 71b6a23ea944c6a30958bd15a69211e1fd521e1e, 4.2affected
- 660d0831d1494a6837b2f810d08b5be092c1f31d and later · before bf20d85a88384574fabb3d53ad62a8af57e7ab11affected · git
- 660d0831d1494a6837b2f810d08b5be092c1f31d and later · before d04958a348e560938410e04a12fb99da9c7e6a00affected · git
- 660d0831d1494a6837b2f810d08b5be092c1f31d and later · before 89812e7957ab0746eab66ed6fc49d52bb4dca250affected · git
- 660d0831d1494a6837b2f810d08b5be092c1f31d and later · before f0a031f7c55ffd944fead1ddaf2aa94df9a158c1affected · git
- 660d0831d1494a6837b2f810d08b5be092c1f31d and later · before fa9542b35ceb4202e8f8d65f440529a63524dca9affected · git
- 660d0831d1494a6837b2f810d08b5be092c1f31d and later · before ec29d0ac29be366450a7faffbcf8cba3a6a3b506affected · git
- 3.2.72 and later · before 3.3affected · semver
- 3.4.111 and later · before 3.5affected · semver
- 3.18.22 and later · before 3.19affected · 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
SUSE:Linux Enterprise High Availability Extension 12 SP5	kernel-default	before 4.12.14-122.222.1	4.12.14-122.222.1
SUSE:Linux Enterprise High Performance Computing 15 SP2-LTSS	kernel-default-base	before 5.3.18-150200.24.197.1.150200.9.101.1	5.3.18-150200.24.197.1.150200.9.101.1
SUSE:Linux Enterprise High Performance Computing 15 SP2-LTSS	kernel-docs	before 5.3.18-150200.24.197.1	5.3.18-150200.24.197.1
SUSE:Linux Enterprise High Performance Computing 15 SP2-LTSS	kernel-obs-build	before 5.3.18-150200.24.197.1	5.3.18-150200.24.197.1
SUSE:Linux Enterprise High Performance Computing 15 SP2-LTSS	kernel-preempt	before 5.3.18-150200.24.197.1	5.3.18-150200.24.197.1
SUSE:Linux Enterprise High Performance Computing 15 SP2-LTSS	kernel-source	before 5.3.18-150200.24.197.1	5.3.18-150200.24.197.1
SUSE:Linux Enterprise High Performance Computing 15 SP2-LTSS	kernel-syms	before 5.3.18-150200.24.197.1	5.3.18-150200.24.197.1
SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSS	kernel-64kb	before 5.3.18-150300.59.167.1	5.3.18-150300.59.167.1
SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSS	kernel-default-base	before 5.3.18-150300.59.167.1.150300.18.98.1	5.3.18-150300.59.167.1.150300.18.98.1
SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSS	kernel-docs	before 5.3.18-150300.59.167.1	5.3.18-150300.59.167.1
SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSS	kernel-obs-build	before 5.3.18-150300.59.167.1	5.3.18-150300.59.167.1
SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSS	kernel-preempt	before 5.3.18-150300.59.167.1	5.3.18-150300.59.167.1
SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSS	kernel-source	before 5.3.18-150300.59.167.1	5.3.18-150300.59.167.1
SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSS	kernel-syms	before 5.3.18-150300.59.167.1	5.3.18-150300.59.167.1
SUSE:Linux Enterprise Live Patching 12 SP5	kgraft-patch-SLE12-SP5_Update_58	before 1-8.3.1	1-8.3.1
SUSE:Linux Enterprise Live Patching 15 SP2	kernel-default	before 5.3.18-150200.24.197.1	5.3.18-150200.24.197.1
SUSE:Linux Enterprise Live Patching 15 SP2	kernel-livepatch-SLE15-SP2_Update_50	before 1-150200.5.3.1	1-150200.5.3.1
SUSE:Linux Enterprise Live Patching 15 SP3	kernel-default	before 5.3.18-150300.59.167.1	5.3.18-150300.59.167.1
SUSE:Linux Enterprise Live Patching 15 SP3	kernel-livepatch-SLE15-SP3_Update_46	before 1-150300.7.3.1	1-150300.7.3.1
SUSE:Linux Enterprise Micro 5.1	kernel-rt	before 5.3.18-150300.175.1	5.3.18-150300.175.1
SUSE:Linux Enterprise Micro 5.1	kernel-source-rt	before 5.3.18-150300.175.1	5.3.18-150300.175.1
SUSE:Linux Enterprise Real Time 12 SP5	kernel-rt	before 4.12.14-10.191.1	4.12.14-10.191.1
SUSE:Linux Enterprise Real Time 12 SP5	kernel-rt_debug	before 4.12.14-10.191.1	4.12.14-10.191.1

+10

Same product

linux: all records

Other highest-scoring records for the same primary product.

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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-2021-47325May 21, 2024 · iommu/arm-smmu: Fix arm_smmu_device refcount leak in address translation
22Monitor
← EarlierCVE-2021-47327May 21, 2024 · iommu/arm-smmu: Fix arm_smmu_device refcount leak when arm_smmu_rpm_get fails
28Monitor
Later →CVE-2021-47329May 21, 2024 · scsi: megaraid_sas: Fix resource leak in case of probe failure
24Monitor

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	3.19	Vendor (CNA)
Linux Linux	3.3	Vendor (CNA)
Linux Linux	3.5	Vendor (CNA)
Linux Linux	4.2	Vendor (CNA)
Linux Linux	89812e7957ab0746eab66ed6fc49d52bb4dca250	Vendor (CNA)
Linux Linux	bf20d85a88384574fabb3d53ad62a8af57e7ab11	Vendor (CNA)
Linux Linux	d04958a348e560938410e04a12fb99da9c7e6a00	Vendor (CNA)
Linux Linux	ec29d0ac29be366450a7faffbcf8cba3a6a3b506	Vendor (CNA)
Linux Linux	f0a031f7c55ffd944fead1ddaf2aa94df9a158c1	Vendor (CNA)
Linux Linux	fa9542b35ceb4202e8f8d65f440529a63524dca9	Vendor (CNA)
debian:linux	5.14.6-1 · Debian:12	Package registry (OSV)
suse:kernel-64kb	5.3.18-150300.59.167.1 · SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSS	Package registry (OSV)
suse:kernel-azure	4.12.14-16.191.1 · SUSE:Linux Enterprise Server 12 SP5	Package registry (OSV)
suse:kernel-default	5.3.18-150300.59.167.1 · SUSE:Linux Enterprise Live Patching 15 SP3	Package registry (OSV)
suse:kernel-default-base	5.3.18-150300.59.167.1.150300.18.98.1 · SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSS	Package registry (OSV)
suse:kernel-docs	5.3.18-150300.59.167.1 · SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSS	Package registry (OSV)
suse:kernel-livepatch-SLE15-SP3_Update_46	1-150300.7.3.1 · SUSE:Linux Enterprise Live Patching 15 SP3	Package registry (OSV)
suse:kernel-obs-build	5.3.18-150300.59.167.1 · SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSS	Package registry (OSV)
suse:kernel-preempt	5.3.18-150300.59.167.1 · SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSS	Package registry (OSV)
suse:kernel-source	5.3.18-150300.59.167.1 · SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSS	Package registry (OSV)
suse:kernel-source-azure	4.12.14-16.191.1 · SUSE:Linux Enterprise Server 12 SP5	Package registry (OSV)
suse:kernel-syms	5.3.18-150300.59.167.1 · SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSS	Package registry (OSV)
suse:kernel-syms-azure	4.12.14-16.191.1 · SUSE:Linux Enterprise Server 12 SP5	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.

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.

TR-24-0519 · May 22, 2024(Linux Kernel Güncellemesi)

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: high · data or configuration can be modified
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: High
Availability impact: High

Weakness class (CWE)

CWE-416 · Use After Free

CVSS vector

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

nvd-primary

Root cause

After a memory region is freed, another reference pointing to it is still used. By then, the same region may have been allocated for different data.

The bug in code

The whole CWE-416 class

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

Vulnerable

1free(dev->buf);
2/* ... another thread is still running ... */
3process(dev->buf);

Fixed

1lock(&dev->lock);
2free(dev->buf);
3dev->buf = NULL;
4unlock(&dev->lock);

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

Fix✗ → ✓Sep 28, 2026, 10:09 PM UTC

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

References

git.kernel.org/stable/c/89812e7957ab0746eab66ed6fc49d52bb4dca250

Show all references (5 more)

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

All records