NVD / CVE Program· CNA Linux

CVE-2025-39873: can: xilinx_can: xcan_write_frame(): fix use-after-free of transmitted SKB

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: 0.16% (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 1139321161a3ba5e45e61e0738b37f42f20bc57a, 668cc1e3bb21101d074e430de1b7ba8fd10189e7, 725b33deebd6e4c96fe7893f384510a54258f28f; azl3 kernel 6.6.104.2-4 on Azure Linux 3.0 6.6.112.1-1.

Low priority for now. Upgrade to Linux Linux 1139321161a3ba5e45e61e0738b37f42f20bc57a, 668cc1e3bb21101d074e430de1b7ba8fd10189e7, 725b33deebd6e4c96fe7893f384510a54258f28f; azl3 kernel 6.6.104.2-4 on Azure Linux 3.0 6.6.112.1-1 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: can: xilinx_can: xcan_write_frame(): fix use-after-free of transmitted SKB can_put_echo_skb() takes ownership of the SKB and it may be freed during or after the call. However, xilinx_can xcan_write_frame() keeps using SKB after the call. Fix that by only calling can_put_echo_skb() after the code is done touching the SKB. The tx_lock is held for the entire xcan_write_frame() execution and also on the can_get_echo_skb() side so the order of operations does not matter. An earlier fix commit 3d3c817c3a40 ("can: xilinx_can: Fix usage of skb memory") did not move the can_put_echo_skb() call far enough. [mkl: add "commit" in front of sha1 in patch description] [mkl: fix indention]

HighCVSS 7.8 · v3.1—No exploit Fix available

Memory safety

BDU:2025-13892

Published: Sep 23, 2025
Updated: Oct 19, 2026
EPSS: 0.1% · 5th 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 · 0.1%

CNA vs NVD score

NVD: 7.8
CNA · Linux: 7.8; agree

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

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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
debian	debian linux	cpe:2.3:o:debian:debian_linux

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

debian debian linux11.0
linux linux kernel5.16 and later · before 6.1.153
linux linux kernel6.2 and later · before 6.6.107
linux linux kernel4.19 and later · before 5.15.194
linux linux kernel6.13 and later · before 6.16.8
linux linux kernel6.7 and later · before 6.12.48
linux linux kernel6.17

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
- 4.19affected
- 1598efe57b3e768056e4ca56cb9cf33111e68d1c and later · before e202ffd9e54538ef67ec301ebd6d9da4823466c9affected · git
- 1598efe57b3e768056e4ca56cb9cf33111e68d1c and later · before 1139321161a3ba5e45e61e0738b37f42f20bc57aaffected · git
- 1598efe57b3e768056e4ca56cb9cf33111e68d1c and later · before 94b050726288a56a6b8ff55aa641f2fedbd3b44caffected · git
- 1598efe57b3e768056e4ca56cb9cf33111e68d1c and later · before 725b33deebd6e4c96fe7893f384510a54258f28faffected · git
- 1598efe57b3e768056e4ca56cb9cf33111e68d1c and later · before 668cc1e3bb21101d074e430de1b7ba8fd10189e7affected · git
- 1598efe57b3e768056e4ca56cb9cf33111e68d1c and later · before ef79f00be72bd81d2e1e6f060d83cf7e425deee4affected · git
- before 4.19not affected · semver
- 5.15.194 and later · up to and including 5.15.*not affected · semver
- 6.1.153 and later · up to and including 6.1.*not affected · 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 6.1.153-1	6.1.153-1
Debian:13	linux	before 6.12.48-1	6.12.48-1
Debian:14	linux	before 6.16.8-1	6.16.8-1

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
90Now
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-2025-39871Sep 23, 2025 · dmaengine: idxd: Remove improper idxd_free
31Monitor
← EarlierCVE-2025-39872Sep 23, 2025 · hsr: hold rcu and dev lock for hsr_get_port_ndev
22Monitor
Later →CVE-2025-39874Sep 23, 2025 · macsec: sync features on RTM_NEWLINK
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	1139321161a3ba5e45e61e0738b37f42f20bc57a	Vendor (CNA)
Linux Linux	668cc1e3bb21101d074e430de1b7ba8fd10189e7	Vendor (CNA)
Linux Linux	725b33deebd6e4c96fe7893f384510a54258f28f	Vendor (CNA)
Linux Linux	94b050726288a56a6b8ff55aa641f2fedbd3b44c	Vendor (CNA)
Linux Linux	e202ffd9e54538ef67ec301ebd6d9da4823466c9	Vendor (CNA)
Linux Linux	ef79f00be72bd81d2e1e6f060d83cf7e425deee4	Vendor (CNA)
azl3 kernel 6.6.104.2-4 on Azure Linux 3.0	6.6.112.1-1 · CBL-Mariner Releases	Microsoft (MSRC)
debian:linux	6.1.153-1 · 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-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/1139321161a3ba5e45e61e0738b37f42f20bc57a

Show all references (6 more)

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

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