Linux Kernel up to 7.3-rc3 lan743x lan743x_rx_process_buffer use after free

CVSS Meta Temp Score
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CTI Interest Score
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9.5$5k-$25k0.00

Summaryinfo

A vulnerability was found in Linux Kernel up to 7.3-rc3. It has been declared as very critical. This affects the function lan743x_rx_process_buffer of the component lan743x. Such manipulation leads to use after free. This vulnerability is traded as CVE-2026-98239. The attack may be launched remotely. There is no exploit available. It is recommended to upgrade the affected component.

Detailsinfo

A vulnerability was found in Linux Kernel up to 7.3-rc3. It has been rated as very critical. Affected by this issue is the function lan743x_rx_process_buffer of the component lan743x. The manipulation with an unknown input leads to a use after free vulnerability. Using CWE to declare the problem leads to CWE-416. Referencing memory after it has been freed can cause a program to crash, use unexpected values, or execute code. Impacted is confidentiality, integrity, and availability. CVE summarizes:

In the Linux kernel, the following vulnerability has been resolved: net: lan743x: fix RX checksum use-after-free lan743x_rx_process_buffer() adds each non-first receive buffer to the head skb's frag_list. On the last descriptor, lan743x_rx_trim_skb() linearizes the head and frees the fragment skb metadata. The checksum-success path then writes ip_summed through the local skb pointer, which still points to the final fragment. This causes a use-after-free write when a packet spans more than one receive buffer. Set ip_summed on the surviving head skb instead. Multi-buffer receive can occur after a live MTU increase because existing ring entries keep their old buffer size until they are replenished. A KUnit test invoking lan743x_rx_process_buffer() with a two-buffer packet produced a one-byte KASAN use-after-free write before this change. The same test passed after the change. The driver object also builds with W=1. This was not tested on physical LAN743x hardware.

The advisory is shared for download at git.kernel.org. This vulnerability is handled as CVE-2026-98239 since 09/25/2026. The exploitation is known to be easy. The attack may be launched remotely. No form of authentication is required for exploitation. There are known technical details, but no exploit is available. The current price for an exploit might be approx. USD $5k-$25k (estimation calculated on 10/06/2026).

Upgrading to version 6.1.189, 6.6.158, 6.12.112, 6.18.54, 7.2.8 or 7.3-rc4 eliminates this vulnerability. Applying the patch 0e52886c4324c9897c2c62f92be3dc8316cee67e/a58024835c704419bb46d2a34e5223f65605f958/6fe5c3a2503983abb431d93faeadfc7f5e6a7e33/5c216bfa9fb7b36804485e67975e9c98055b31ef/161a403c8625e152de03d1da22bbf9cda6dc9f9f/a9ce4053dc945c5372dedba5017ee675b30dc0c5 is able to eliminate this problem. The best possible mitigation is suggested to be upgrading to the latest version.

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Productinfo

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Version

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CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 10.0
VulDB Meta Temp Score: 9.5

VulDB Base Score: 10.0
VulDB Temp Score: 9.5
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AVACAuCIA
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Use after free
CWE: CWE-416 / CWE-119
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Kernel 6.1.189/6.6.158/6.12.112/6.18.54/7.2.8/7.3-rc4
Patch: 0e52886c4324c9897c2c62f92be3dc8316cee67e/a58024835c704419bb46d2a34e5223f65605f958/6fe5c3a2503983abb431d93faeadfc7f5e6a7e33/5c216bfa9fb7b36804485e67975e9c98055b31ef/161a403c8625e152de03d1da22bbf9cda6dc9f9f/a9ce4053dc945c5372dedba5017ee675b30dc0c5

Timelineinfo

09/25/2026 CVE reserved
10/06/2026 +11 days Advisory disclosed
10/06/2026 +0 days VulDB entry created
10/06/2026 +0 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2026-98239 (🔒)
GCVE (CVE): GCVE-0-2026-98239
GCVE (VulDB): GCVE-100-414224

Entryinfo

Created: 10/06/2026 13:49
Changes: 10/06/2026 13:49 (59)
Complete: 🔍
Cache ID: 216::103

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