CVE-2026-98581

Description

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.

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EPSS — Exploit Prediction

0.0022

Probability of exploitation

0.12%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

References

Other References

https://git.kernel.org/stable/c/320a2ff49bdce3f9a437b9a9ff341ff27d3bdbf1 https://git.kernel.org/stable/c/7fb2c0eeb79bfad64065f539a453138abd0edda6 https://git.kernel.org/stable/c/812731dd8511f5768f4ff279b3c18d85cd21da4b https://git.kernel.org/stable/c/b94cf09720543cc34256c7aa88f8059cbe7c0419 https://git.kernel.org/stable/c/bf1460acdf8cf5a07c819f59785d40f20d113099 https://git.kernel.org/stable/c/c1e9ed52a6697354366dddf190fbacee8ed2f7c5 https://git.kernel.org/stable/c/dba1d9c7134afcb4b1bfad8c1b1b3f0ab5189b08 https://git.kernel.org/stable/c/dd2d24add86b3b63cd87cf2feff98ae119ba19a6

Frequently Asked Questions

What is CVE-2026-98581? +

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.

How do I check if I'm vulnerable to CVE-2026-98581? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.