Linux Kernel up to 6.18.39/7.1.4/7.2-rc1 fbnic fbnic_tx_lso.isra fbnic_tx_lso.isra.0 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, which was classified as very critical, was found in Linux Kernel up to 6.18.39/7.1.4/7.2-rc1. This vulnerability affects the function fbnic_tx_lso.isra.0 of the file fbnic_tx_lso.isra of the component fbnic. The manipulation results in use after free. This vulnerability is identified as CVE-2026-72393. The attack can be executed remotely. There is not any exploit available.

Detailsinfo

A vulnerability, which was classified as very critical, was found in Linux Kernel up to 6.18.39/7.1.4/7.2-rc1. Affected is the function fbnic_tx_lso.isra.0 of the file fbnic_tx_lso.isra of the component fbnic. The manipulation with an unknown input leads to a use after free vulnerability. CWE is classifying the issue as CWE-416. Referencing memory after it has been freed can cause a program to crash, use unexpected values, or execute code. This is going to have an impact on confidentiality, integrity, and availability. CVE summarizes:

In the Linux kernel, the following vulnerability has been resolved: eth: fbnic: don't cache shinfo across skb realloc fbnic_tx_lso() calls skb_cow_head() which may reallocate the skb including the shared info. We can't use the pointer calculated before the call. BUG: KASAN: slab-use-after-free in fbnic_tx_lso.isra.0+0x668/0x8e0 Read of size 4 at addr ff110000262edd98 by task swapper/5/0 Call Trace: fbnic_tx_lso.isra.0+0x668/0x8e0 fbnic_xmit_frame+0x622/0xba0 dev_hard_start_xmit+0xf4/0x620 Allocated by task 8653: __alloc_skb+0x11e/0x5f0 alloc_skb_with_frags+0xcc/0x6c0 sock_alloc_send_pskb+0x327/0x3f0 __ip_append_data+0x188b/0x47a0 ip_make_skb+0x24a/0x300 udp_sendmsg+0x14d2/0x21e0 Freed by task 0: kfree+0x123/0x5a0 pskb_expand_head+0x36c/0xfa0 fbnic_tx_lso.isra.0+0x500/0x8e0 fbnic_xmit_frame+0x622/0xba0 dev_hard_start_xmit+0xf4/0x620 sch_direct_xmit+0x25b/0x1100 The buggy address belongs to the object at ff110000262edc40 which belongs to the cache skbuff_small_head of size 640 The buggy address is located 344 bytes inside of freed 640-byte region [ff110000262edc40, ff110000262ede

The advisory is shared for download at git.kernel.org. This vulnerability is traded as CVE-2026-72393 since 08/09/2026. The exploitability is told to be easy. It is possible to launch the attack remotely. The exploitation doesn't require any form of authentication. 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 08/15/2026).

Upgrading to version 6.18.40, 7.1.5 or 7.2-rc2 eliminates this vulnerability. Applying the patch 83df3e2594cd78aa40b1246a19879abb4891945b/21f304c2aae46625e050c28d979f4b9d83faa85e/62b68b774f06bf52e329f254f0199bc43d350ccf is able to eliminate this problem.

Once again VulDB remains the best source for vulnerability data.

Productinfo

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Vendor

Name

Version

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Website

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
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 6.18.40/7.1.5/7.2-rc2
Patch: 83df3e2594cd78aa40b1246a19879abb4891945b/21f304c2aae46625e050c28d979f4b9d83faa85e/62b68b774f06bf52e329f254f0199bc43d350ccf

Timelineinfo

08/09/2026 CVE reserved
08/15/2026 +6 days Advisory disclosed
08/15/2026 +0 days VulDB entry created
08/15/2026 +0 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2026-72393 (🔒)
GCVE (CVE): GCVE-0-2026-72393
GCVE (VulDB): GCVE-100-390756

Entryinfo

Created: 08/15/2026 14:46
Changes: 08/15/2026 14:46 (60)
Complete: 🔍
Cache ID: 216::103

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