NVD / CVE Program· CNA Linux

CVE-2025-37838: HSI: ssi_protocol: Fix use after free vulnerability in ssi_protocol Driver Due to Race Condition

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: 0.24% (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 4a8c29beb8a02b5a0a9d77d608aa14b6f88a6b86, 4b4194c9a7a8f92db39e8e86c85f4fb12ebbec4f, 58eb29dba712ab0f13af59ca2fe545f5ce360e78; azl3 kernel 6.6.85.1-4 on Azure Linux 3.0 6.6.92.2-1.

Low priority for now. Upgrade to Linux Linux 4a8c29beb8a02b5a0a9d77d608aa14b6f88a6b86, 4b4194c9a7a8f92db39e8e86c85f4fb12ebbec4f, 58eb29dba712ab0f13af59ca2fe545f5ce360e78; azl3 kernel 6.6.85.1-4 on Azure Linux 3.0 6.6.92.2-1 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: HSI: ssi_protocol: Fix use after free vulnerability in ssi_protocol Driver Due to Race Condition In the ssi_protocol_probe() function, &ssi->work is bound with ssip_xmit_work(), In ssip_pn_setup(), the ssip_pn_xmit() function within the ssip_pn_ops structure is capable of starting the work. If we remove the module which will call ssi_protocol_remove() to make a cleanup, it will free ssi through kfree(ssi), while the work mentioned above will be used. The sequence of operations that may lead to a UAF bug is as follows: CPU0 CPU1 | ssip_xmit_work ssi_protocol_remove | kfree(ssi); | | struct hsi_client *cl = ssi->cl; | // use ssi Fix it by ensuring that the work is canceled before proceeding with the cleanup in ssi_protocol_remove().

HighCVSS 7.8 · v3.1—No exploit Fix available

BDU:2025-12074

Published: Apr 18, 2025
Updated: Aug 5, 2026
EPSS: 0.2% · 16th percentile
CWE: CWE-416

Report tools

JSON

Action score

Monitor

Low priority for now.

CVSS: 31 / 40 · 7.8 / 10
CISA KEV: 0 / 30 · Not listed
EPSS: 0 / 30 · 0.2%

CISA SSVC decision

Exploitation: none
Automatable: no
Technical impact: total

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD: —
CNA · Linux: 7.8; NVD has not scored this yet; the score shown is the CNA’s.

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

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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.

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 6.1.135
linux linux kernel6.2 and later · before 6.6.88
linux linux kernel6.7 and later · before 6.12.24
linux linux kernel6.13 and later · before 6.13.12
linux linux kernel6.14 and later · before 6.14.3

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
- 4.8affected
- df26d639e2f4628732a8da5a0f71e4e652ce809b and later · before d03abc1c2b21324550fa71e12d53e7d3498e0af6affected · git
- df26d639e2f4628732a8da5a0f71e4e652ce809b and later · before 4a8c29beb8a02b5a0a9d77d608aa14b6f88a6b86affected · git
- df26d639e2f4628732a8da5a0f71e4e652ce809b and later · before 72972552d0d0bfeb2dec5daf343a19018db36ffaaffected · git
- df26d639e2f4628732a8da5a0f71e4e652ce809b and later · before d58493832e284f066e559b8da5ab20c15a2801d3affected · git
- df26d639e2f4628732a8da5a0f71e4e652ce809b and later · before 58eb29dba712ab0f13af59ca2fe545f5ce360e78affected · git
- df26d639e2f4628732a8da5a0f71e4e652ce809b and later · before ae5a6a0b425e8f76a9f0677e50796e494e89b088affected · git
- df26d639e2f4628732a8da5a0f71e4e652ce809b and later · before 834e602d0cc7c743bfce734fad4a46cefc0f9ab1affected · git
- df26d639e2f4628732a8da5a0f71e4e652ce809b and later · before 4b4194c9a7a8f92db39e8e86c85f4fb12ebbec4faffected · git
- df26d639e2f4628732a8da5a0f71e4e652ce809b and later · before e3f88665a78045fe35c7669d2926b8d97b892c11affected · git

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 6.1.135-1	6.1.135-1
Debian:13	linux	before 6.12.25-1	6.12.25-1

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
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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-2025-40325Apr 18, 2025 · md/raid10: wait barrier before returning discard request with REQ_NOWAIT
22Monitor
← EarlierCVE-2025-40364Apr 18, 2025 · io_uring: fix io_req_prep_async with provided buffers
31Monitor
Later →CVE-2024-58099Apr 29, 2025 · vmxnet3: Fix packet corruption in vmxnet3_xdp_xmit_frame
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 / package	Fixed version	Source
Linux Linux	4a8c29beb8a02b5a0a9d77d608aa14b6f88a6b86	Vendor (CNA)
Linux Linux	4b4194c9a7a8f92db39e8e86c85f4fb12ebbec4f	Vendor (CNA)
Linux Linux	58eb29dba712ab0f13af59ca2fe545f5ce360e78	Vendor (CNA)
Linux Linux	72972552d0d0bfeb2dec5daf343a19018db36ffa	Vendor (CNA)
Linux Linux	834e602d0cc7c743bfce734fad4a46cefc0f9ab1	Vendor (CNA)
Linux Linux	ae5a6a0b425e8f76a9f0677e50796e494e89b088	Vendor (CNA)
Linux Linux	d03abc1c2b21324550fa71e12d53e7d3498e0af6	Vendor (CNA)
Linux Linux	d58493832e284f066e559b8da5ab20c15a2801d3	Vendor (CNA)
Linux Linux	e3f88665a78045fe35c7669d2926b8d97b892c11	Vendor (CNA)
azl3 kernel 6.6.85.1-4 on Azure Linux 3.0	6.6.92.2-1 · CBL-Mariner Releases	Microsoft (MSRC)
debian:linux	6.1.135-1 · Debian:12	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).

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-secondary

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, 10:10 PM UTC

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

References

git.kernel.org/stable/c/4a8c29beb8a02b5a0a9d77d608aa14b6f88a6b86

Show all references (10 more)

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

All records