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CVE-2026-23461— Bluetooth: L2CAP: Fix use-after-free in l2cap_unregister_user

Quick assessment

Affected
Linux Linux
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

Linux kernel是美国Linux基金会的开源操作系统Linux所使用的内核。 Linux kernel存在安全漏洞，该漏洞源于l2cap_unregister_user函数存在释放后重用，可能导致列表损坏。

CVSS 8.8 · High EPSS 0.19% · P8

Possible ATT&CK Techniques 1 AI

T1203 · Exploitation for Client Execution

Affected Version Matrix 16

VendorProduct Version RangeStatus
Linux Linux efc30877bd4bc85fefe98d80af60fafc86e5775e< 11a87dd5df428a4b79a84d2790cac7f3c73f1f0d affected
f87271d21dd4ee83857ca11b94e7b4952749bbae< c22a5e659959eb77c2fbb58a5adfaf3c3dab7abf affected
ab4eedb790cae44313759b50fe47da285e2519d5< da3000cbe4851458a22be38bb18c0689c39fdd5f affected
ab4eedb790cae44313759b50fe47da285e2519d5< 71030f3b3015a412133a805ff47970cdcf30c2b8 affected
ab4eedb790cae44313759b50fe47da285e2519d5< 752a6c9596dd25efd6978a73ff21f3b592668f4a affected
18ab6b6078fa8191ca30a3065d57bf35d5635761 affected
6.6.84< 6.6.130 affected
6.12.20< 6.12.78 affected
… +8 more rows
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I. Basic Information for CVE-2026-23461

Vulnerability Information
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Vulnerability Title
Bluetooth: L2CAP: Fix use-after-free in l2cap_unregister_user
Source: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved: Bluetooth: L2CAP: Fix use-after-free in l2cap_unregister_user After commit ab4eedb790ca ("Bluetooth: L2CAP: Fix corrupted list in hci_chan_del"), l2cap_conn_del() uses conn->lock to protect access to conn->users. However, l2cap_register_user() and l2cap_unregister_user() don't use conn->lock, creating a race condition where these functions can access conn->users and conn->hchan concurrently with l2cap_conn_del(). This can lead to use-after-free and list corruption bugs, as reported by syzbot. Fix this by changing l2cap_register_user() and l2cap_unregister_user() to use conn->lock instead of hci_dev_lock(), ensuring consistent locking for the l2cap_conn structure.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Source: CVE Program / CVE List V5
Vulnerability Type
N/A
Source: CVE Program / CVE List V5
Vulnerability Title
Linux kernel 安全漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
Linux kernel是美国Linux基金会的开源操作系统Linux所使用的内核。 Linux kernel存在安全漏洞，该漏洞源于l2cap_unregister_user函数存在释放后重用，可能导致列表损坏。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

Vendor Product Affected Versions CPE Subscribe
Linux Linux efc30877bd4bc85fefe98d80af60fafc86e5775e ~ 11a87dd5df428a4b79a84d2790cac7f3c73f1f0d -
Linux Linux 6.14 -

II. Public POCs for CVE-2026-23461

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III. Intelligence Information for CVE-2026-23461

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Same Patch Batch · Linux · 2026-04-03 · 71 CVEs total

CVE-2026-31402 9.8 CRITICAL nfsd: fix heap overflow in NFSv4.0 LOCK replay cache
CVE-2026-23450 9.8 CRITICAL net/smc: fix NULL dereference and UAF in smc_tcp_syn_recv_sock()
CVE-2026-23427 9.8 CRITICAL ksmbd: fix use-after-free in durable v2 replay of active file handles
CVE-2026-23428 9.8 CRITICAL ksmbd: fix use-after-free of share_conf in compound request
CVE-2026-23455 9.1 CRITICAL netfilter: nf_conntrack_h323: check for zero length in DecodeQ931()
CVE-2026-23425 8.8 HIGH KVM: arm64: Fix ID register initialization for non-protected pKVM guests
CVE-2026-23462 8.8 HIGH Bluetooth: HIDP: Fix possible UAF
CVE-2026-23457 8.6 HIGH netfilter: nf_conntrack_sip: fix Content-Length u32 truncation in sip_help_tcp()
CVE-2026-23459 8.2 HIGH ip_tunnel: adapt iptunnel_xmit_stats() to NETDEV_PCPU_STAT_DSTATS
CVE-2026-23456 8.2 HIGH netfilter: nf_conntrack_h323: fix OOB read in decode_int() CONS case
CVE-2026-31393 8.1 HIGH Bluetooth: L2CAP: Validate L2CAP_INFO_RSP payload length before access
CVE-2026-31392 8.1 HIGH smb: client: fix krb5 mount with username option
CVE-2026-23466 7.8 HIGH drm/xe: Open-code GGTT MMIO access protection
CVE-2026-23432 7.8 HIGH mshv: Fix use-after-free in mshv_map_user_memory error path
CVE-2026-31398 7.8 HIGH mm/rmap: fix incorrect pte restoration for lazyfree folios
CVE-2026-23458 7.8 HIGH netfilter: ctnetlink: fix use-after-free in ctnetlink_dump_exp_ct()
CVE-2026-23437 7.8 HIGH net: shaper: protect late read accesses to the hierarchy
CVE-2026-23444 7.8 HIGH wifi: mac80211: always free skb on ieee80211_tx_prepare_skb() failure
CVE-2026-23449 7.8 HIGH net/sched: teql: Fix double-free in teql_master_xmit
CVE-2026-23445 7.8 HIGH igc: fix page fault in XDP TX timestamps handling

Showing top 20 of 71 CVEs. View all on vendor page &rarr; →

IV. Related Vulnerabilities

Same product: Linux
Same vendor: Linux

V. Comments for CVE-2026-23461

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