Linux Kernel up to 7.3-rc4 NFC LLCP nfc_llcp_recv_dm race condition

CVSS Meta Temp Score
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CTI Interest Score
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8.6$0-$5k1.37

Summaryinfo

A vulnerability has been found in Linux Kernel up to 7.3-rc4 and classified as very critical. This affects the function nfc_llcp_recv_dm of the component NFC LLCP. This manipulation causes race condition. The identification of this vulnerability is CVE-2026-98581. It is possible to initiate the attack remotely. There is no exploit available. The affected component should be upgraded.

Detailsinfo

A vulnerability was found in Linux Kernel up to 7.3-rc4. It has been declared as very critical. Affected by this vulnerability is the function nfc_llcp_recv_dm of the component NFC LLCP. The manipulation with an unknown input leads to a race condition vulnerability. The CWE definition for the vulnerability is CWE-362. The product contains a code sequence that can run concurrently with other code, and the code sequence requires temporary, exclusive access to a shared resource, but a timing window exists in which the shared resource can be modified by another code sequence that is operating concurrently. 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: nfc: llcp: Fix list corruption / refcount desync in nfc_llcp_recv_dm() nfc_llcp_recv_dm() handles DM(NOBOUND)/DM(REJ) for a socket that is still linked on local->connecting_sockets: it looks the socket up with nfc_llcp_connecting_sock_get(), sets sk->sk_state = LLCP_CLOSED and returns, without taking the socket lock and without unlinking the socket from the connecting_sockets list. llcp_sock_release() selects the list to unlink from by sk_state: a socket in LLCP_CONNECTING is unlinked from connecting_sockets, otherwise from the sockets list. Because recv_dm left the socket physically on connecting_sockets but in the LLCP_CLOSED state, release() takes the else branch and calls nfc_llcp_sock_unlink(&local->sockets, sk). That runs sk_del_node_init() while holding sockets.lock, i.e. it removes the socket from the connecting_sockets hlist under the wrong lock. A concurrent connect() linking another socket onto connecting_sockets under connecting_sockets.lock then mutates the same hlist unserialized, which corrupts the list and desyncs the sk_add_node()/sk_del_node_init() sock_hold()/__sock_put() pairing. An unprivileged local process holding LLCP sockets, with the DM supplied by the remote peer over an established LLCP link, can drive this to leak kernel sockets without bound (the mis-decrement goes through the non-freeing __sock_put() path, so the object is never released), leading to memory exhaustion / DoS. This is the same class of bug that was fixed in the sibling handler nfc_llcp_recv_cc() by commit b493ea2765cc ("nfc: llcp: Fix use-after-free race in nfc_llcp_recv_cc()"); recv_dm did not receive the equivalent fix. Fix it the same way: take lock_sock(), re-check that the socket is still hashed (release() may have won the race), and for the NOBOUND/REJ case unlink it from connecting_sockets before moving it to LLCP_CLOSED. The unlink drops the connecting_sockets membership reference via sk_del_node_init(), leaving the socket unhashed, so the later nfc_llcp_sock_unlink() in llcp_sock_release() becomes a no-op and no double put occurs.

The advisory is shared at git.kernel.org. This vulnerability is known as CVE-2026-98581 since 09/25/2026. The exploitation appears to be easy. The attack can be launched remotely. It demands that the victim is doing some kind of user interaction. Technical details are known, but no exploit is available. The price for an exploit might be around USD $0-$5k 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 dd2d24add86b3b63cd87cf2feff98ae119ba19a6/812731dd8511f5768f4ff279b3c18d85cd21da4b/dba1d9c7134afcb4b1bfad8c1b1b3f0ab5189b08/c1e9ed52a6697354366dddf190fbacee8ed2f7c5/7fb2c0eeb79bfad64065f539a453138abd0edda6/b94cf09720543cc34256c7aa88f8059cbe7c0419/320a2ff49bdce3f9a437b9a9ff341ff27d3bdbf1/bf1460acdf8cf5a07c819f59785d40f20d113099 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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CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 9.0
VulDB Meta Temp Score: 8.6

VulDB Base Score: 9.0
VulDB Temp Score: 8.6
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: Race condition
CWE: CWE-362
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: dd2d24add86b3b63cd87cf2feff98ae119ba19a6/812731dd8511f5768f4ff279b3c18d85cd21da4b/dba1d9c7134afcb4b1bfad8c1b1b3f0ab5189b08/c1e9ed52a6697354366dddf190fbacee8ed2f7c5/7fb2c0eeb79bfad64065f539a453138abd0edda6/b94cf09720543cc34256c7aa88f8059cbe7c0419/320a2ff49bdce3f9a437b9a9ff341ff27d3bdbf1/bf1460acdf8cf5a07c819f59785d40f20d113099

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-2026-98581 (🔒)
GCVE (CVE): GCVE-0-2026-98581
GCVE (VulDB): GCVE-100-422089

Entryinfo

Created: 10/18/2026 20:17
Changes: 10/18/2026 20:17 (59)
Complete: 🔍
Cache ID: 216::103

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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