Linux Kernel up to 7.3-rc4 llc use after free

CVSS Meta Temp Score
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Current Exploit Price (≈)
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CTI Interest Score
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9.5$5k-$25k0.91

Summaryinfo

A vulnerability was found in Linux Kernel up to 7.3-rc4 and classified as very critical. This vulnerability affects the function llc_mac_hdr_init/llc_conn_ac_resend_i_xxx_x_set_0_or_send_rr/llc_sap_action_send_xid_r/llc_sap_action_send_test_r of the component llc. Executing a manipulation can lead to use after free. This vulnerability is tracked as CVE-2026-98555. The attack can be launched remotely. No exploit exists. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability was found in Linux Kernel up to 7.3-rc4. It has been declared as very critical. This vulnerability affects the function llc_mac_hdr_init/llc_conn_ac_resend_i_xxx_x_set_0_or_send_rr/llc_sap_action_send_xid_r/llc_sap_action_send_test_r of the component llc. 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. CVE summarizes:

In the Linux kernel, the following vulnerability has been resolved: llc: fix skb UAF and leaks on llc_mac_hdr_init() failure In llc_conn_ac_resend_i_xxx_x_set_0_or_send_rr(), if llc_mac_hdr_init() fails, kfree_skb(skb) is called instead of kfree_skb(nskb). This leaks the newly allocated nskb, reads from the freed skb via LLC_I_GET_NR(pdu), and double-frees skb when llc_conn_state_process() drops its reference. In llc_sap_action_send_xid_r() and llc_sap_action_send_test_r(), nskb is leaked if llc_mac_hdr_init() returns an error. Free nskb in all three error paths.

The advisory is available at git.kernel.org. This vulnerability was named CVE-2026-98555 since 09/25/2026. The exploitation appears to be easy. The attack can be initiated remotely. No form of authentication is required for a successful exploitation. Technical details are known, but there is no available exploit. The structure of the vulnerability defines a possible price range of USD $5k-$25k at the moment (estimation calculated on 10/18/2026).

Upgrading to version 5.10.271, 5.15.222, 6.1.189, 6.6.158, 6.12.112, 6.18.55, 7.2.9 or 7.3-rc5 eliminates this vulnerability. Applying the patch fec0fe6838a7f45175667701fb51abb23a6ffb1e/b859ba18b5a1067f71db5618c6a4a70d55fa308b/8b855b645841b5a04e20339a22bb6d593c9b790d/d360b31f1a3666579422872aa7d1a751e20b76f9/060f827aa3dc47939ee306da715cd6700d129616/41dcae82bece9f106b4dff0ee777bba8d157c8a8/cb3528ad8bb46fa6252f5d14ced7febddc18515d/72f9dd522f8d6c5a00be9695c7bb74631eb5069e is able to eliminate this problem. The best possible mitigation is suggested to be upgrading to the latest version.

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Productinfo

Type

Vendor

Name

Version

License

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 5.10.271/5.15.222/6.1.189/6.6.158/6.12.112/6.18.55/7.2.9/7.3-rc5
Patch: fec0fe6838a7f45175667701fb51abb23a6ffb1e/b859ba18b5a1067f71db5618c6a4a70d55fa308b/8b855b645841b5a04e20339a22bb6d593c9b790d/d360b31f1a3666579422872aa7d1a751e20b76f9/060f827aa3dc47939ee306da715cd6700d129616/41dcae82bece9f106b4dff0ee777bba8d157c8a8/cb3528ad8bb46fa6252f5d14ced7febddc18515d/72f9dd522f8d6c5a00be9695c7bb74631eb5069e

Timelineinfo

09/25/2026 CVE reserved
10/18/2026 +23 days Advisory disclosed
10/18/2026 +0 days VulDB entry created
10/18/2026 +0 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2026-98555 (🔒)
GCVE (CVE): GCVE-0-2026-98555
GCVE (VulDB): GCVE-100-422062

Entryinfo

Created: 10/18/2026 20:06
Changes: 10/18/2026 20:06 (59)
Complete: 🔍
Cache ID: 216::103

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