Linux Kernel up to 7.3-rc3 flowtable nf_ct_put use after free

CVSS Meta Temp Score
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CTI Interest Score
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9.5$5k-$25k0.29

Summaryinfo

A vulnerability, which was classified as very critical, has been found in Linux Kernel up to 7.3-rc3. This impacts the function nf_ct_put of the component flowtable. This manipulation causes use after free. This vulnerability is tracked as CVE-2026-98320. The attack is possible to be carried out remotely. No exploit exists. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability has been found in Linux Kernel up to 7.3-rc3 and classified as very critical. Affected by this vulnerability is the function nf_ct_put of the component flowtable. The manipulation with an unknown input leads to a use after free vulnerability. The CWE definition for the vulnerability is CWE-416. Referencing memory after it has been freed can cause a program to crash, use unexpected values, or execute code. As an impact it is known to affect confidentiality, integrity, and availability. The summary by CVE is:

In the Linux kernel, the following vulnerability has been resolved: netfilter: flowtable: hold reference on ct until flow is released nf_ct_put() releases the ct->ext area inmediately, the rcu typesafe semantics also allow to refer to the wrong conntrack from the flowtable datapath. Hold reference on ct until flow is released after rcu grace period. Add rcu_barrier() on module exit path, to ensure pending flow entries are release before module goes away.

It is possible to read the advisory at git.kernel.org. This vulnerability is known as CVE-2026-98320 since 09/25/2026. The exploitation appears to be easy. The attack can be launched remotely. The exploitation doesn't need any form of authentication. Technical details of the vulnerability are known, but there is no available exploit. The pricing for an exploit might be around USD $5k-$25k at the moment (estimation calculated on 10/06/2026).

Upgrading to version 5.10.271, 5.15.222, 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 93ff1594be1aad4da364462dd8db050ebcfda2de/eed6997e8dc40593a539fcc722e7ed51b18db86c/61c6688be282277c6e91ab286a7acd0ae8681ac6/a43cd2b67b91e943273c913237a7a88c50cdcfbc/8274cdc5f9c57e17ed77fc4ba76212536c840f25/12c1ac230f4ca16e0017b62a963ab75e0b48074f/d9e6175a3ee48209ee65f294fc567b4e16b29b74/e75a9fa1d44bcbd66ea02e8781bcca6ea4076e0d is able to eliminate this problem. The best possible mitigation is suggested to be upgrading to the latest version.

Be aware that VulDB is the high quality source for vulnerability data.

Productinfo

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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
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 5.10.271/5.15.222/6.1.189/6.6.158/6.12.112/6.18.54/7.2.8/7.3-rc4
Patch: 93ff1594be1aad4da364462dd8db050ebcfda2de/eed6997e8dc40593a539fcc722e7ed51b18db86c/61c6688be282277c6e91ab286a7acd0ae8681ac6/a43cd2b67b91e943273c913237a7a88c50cdcfbc/8274cdc5f9c57e17ed77fc4ba76212536c840f25/12c1ac230f4ca16e0017b62a963ab75e0b48074f/d9e6175a3ee48209ee65f294fc567b4e16b29b74/e75a9fa1d44bcbd66ea02e8781bcca6ea4076e0d

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-2026-98320 (🔒)
GCVE (CVE): GCVE-0-2026-98320
GCVE (VulDB): GCVE-100-414247

Entryinfo

Created: 10/06/2026 14:00
Changes: 10/06/2026 14:00 (59)
Complete: 🔍
Cache ID: 216::103

Be aware that VulDB is the high quality source for vulnerability data.

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