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CVE-2026-80849— net/tcp-ao: fix use-after-free of current_key on reconnect to another peer

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基金会开源的一个操作系统内核。 Linux kernel 6.7版本存在安全漏洞，该漏洞源于在重新连接到其他对端时current_key释放后重用，可能导致读取已释放内存中的流量密钥。

AI Predicted 7.8 Difficulty: Hard EPSS 0.17% · P6

Affected Version Matrix 12

VendorProduct Version RangeStatus
Linux Linux 0a3a809089eb1d4a0a2fd0c16b520d603988c859< 84a93b4e012587d0a4a84ffb23ec6da18e9d85f9 affected
0a3a809089eb1d4a0a2fd0c16b520d603988c859< 73fde8fe4469f4ed8f0afcc0b9d6413002a9e6b3 affected
0a3a809089eb1d4a0a2fd0c16b520d603988c859< e54ad693eddb40c595add013f545354c538e325b affected
0a3a809089eb1d4a0a2fd0c16b520d603988c859< 2857dcbd03cf3354af0fba1b65c6a260fb43811a affected
0a3a809089eb1d4a0a2fd0c16b520d603988c859< da4471557f279d0f56605158a625bb6e49ef7d41 affected
6.7 affected
< 6.7 unaffected
6.12.108≤ 6.12.* unaffected
… +4 more rows
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I. Basic Information for CVE-2026-80849

Vulnerability Information
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Vulnerability Title
net/tcp-ao: fix use-after-free of current_key on reconnect to another peer
Source: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved: net/tcp-ao: fix use-after-free of current_key on reconnect to another peer tcp_inbound_ao_hash() is called before bh_lock_sock_nested() is taken, with only rcu_read_lock() held. On the fast path for established sockets, if the rnext_keyid sent by the peer differs from current_key->sndid, the key the peer asked for is looked up and stored in current_key. The lookup is inside the RCU read side, but current_key outlives it. When the socket is disconnected and connect() is called again for another peer, tcp_ao_connect_init() unlinks every key that does not match the new peer and frees it with call_rcu(). If current_key points at such a key, it is cleared to NULL. The fast path reads sk_state only once on entry, so a softirq that got into it while the socket was still established can update current_key after that loop has already run. The update is inside the RCU read side, so it comes before the call_rcu() callback, and once the callback frees the key, current_key is left pointing at freed memory. The next transmission picks that pointer up in tcp_get_current_key(). tcp_ao_transmit_skb() then reads the traffic key from the freed object, which is the use-after-free. Wait for one grace period before unlinking, and only if a key is going to be removed. By the time tcp_connect() runs the socket is already in TCP_SYN_SENT, and TCP_AO_ESTABLISHED does not contain TCPF_SYN_SENT, so a softirq entering after the wait cannot reach the fast path, and the ones already in it have finished. The existing NULL handling in the loop is then enough.
Source: CVE Program / CVE List V5
CVSS Information
N/A
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基金会开源的一个操作系统内核。 Linux kernel 6.7版本存在安全漏洞，该漏洞源于在重新连接到其他对端时current_key释放后重用，可能导致读取已释放内存中的流量密钥。
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 0a3a809089eb1d4a0a2fd0c16b520d603988c859 ~ 84a93b4e012587d0a4a84ffb23ec6da18e9d85f9 -
Linux Linux 6.7 -

II. Public POCs for CVE-2026-80849

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III. Intelligence Information for CVE-2026-80849

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Patches & Fixes for CVE-2026-80849 (5)

Same Patch Batch · Linux · 2026-09-04 · 156 CVEs total

CVE-2026-80865 bpf: Add missing access_ok call to copy_user_syms
CVE-2026-80856 fuse: fix invalidate lock leak on setattr writeback failure
CVE-2026-80857 fuse: wait for FR_FINISHED on abort_on_kill to prevent use-after-free
CVE-2026-80858 fuse: publish io-uring queues with release semantics
CVE-2026-80859 fuse: fix missing barrier when checking io-uring readiness
CVE-2026-80860 fuse: fix race between interrupt and resend
CVE-2026-80861 usb: xhci: bail out of setup if the controller is inaccessible
CVE-2026-80862 nvme-tcp: fix usage of page_frag_cache
CVE-2026-80863 RDMA/rxe: Fix OOB in free_rd_atomic_resources()
CVE-2026-80864 RDMA/rxe: Fix responder UAF on IB_QP_MAX_DEST_RD_ATOMIC modify_qp
CVE-2026-80870 drm/amdkfd: Validate CRIU-restored IDs before idr_alloc
CVE-2026-80874 arm64: dts: renesas: ironhide: Describe inline ECC carveouts
CVE-2026-80873 KVM: arm64: nv: Write ESR_EL2 for injected nested SError exceptions
CVE-2026-80872 ALSA: hda/tas2781: Cancel async firmware request at unbind
CVE-2026-80871 crypto: xilinx-trng - Remove crypto_rng interface
CVE-2026-80868 ntfs3: Allocate iomap inline_data using alloc_page
CVE-2026-80866 tipc: avoid busy looping in tipc_exit_net()
CVE-2026-80867 alpha/PCI: Add security_locked_down() check to pci_mmap_resource()
CVE-2026-80855 fuse: fix invalidate lock leak on open O_TRUNC DAX failure
CVE-2026-80869 ntfs: bound the attribute-list entry in ntfs_read_inode_mount()

Showing top 20 of 156 CVEs. View all on vendor page &rarr; →

IV. Related Vulnerabilities

Same product: Linux
Same vendor: Linux

V. Comments for CVE-2026-80849

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