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CVE-2026-99138— tcp: fix use-after-free in do_tcp_getsockopt(TCP_CC_INFO)

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.

在 Linux 内核中，以下漏洞已得到修复： tcp: 修复 do_tcp_getsockopt(TCP_CC_INFO) 中的释放后使用（use-after-free）漏洞 do_tcp_getsockopt() 函数在读取 icsk->icsk_ca_ops 并解引用 get_info 函数指针时，未加 rcu_read_lock() 保护。当使用 BPF struct_ops 拥塞控制时，ca_ops 可能指向动态分配的内存，而该内存可能被并发释放，导致内核在解引用或通过该陈旧指针调用时触发释放后使用漏洞。

AI Predicted 7.8 Difficulty: Moderate

Possible ATT&CK Techniques 1 AI

T1068.001
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I. Basic Information for CVE-2026-99138

Vulnerability Information
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Vulnerability Title
tcp: fix use-after-free in do_tcp_getsockopt(TCP_CC_INFO)
Source: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved: tcp: fix use-after-free in do_tcp_getsockopt(TCP_CC_INFO) do_tcp_getsockopt() reads icsk->icsk_ca_ops and dereferences the get_info function pointer without rcu_read_lock(). With BPF struct_ops congestion control, ca_ops can point to dynamically allocated memory that is freed concurrently, resulting in a use-after-free when the kernel dereferences or calls through the stale pointer. BUG: KASAN: slab-use-after-free in do_tcp_getsockopt+0x2037/0x23e0 Read of size 8 at addr ffff888013701258 by task exploit/149 do_tcp_getsockopt+0x2037/0x23e0 (net/ipv4/tcp.c:4564) tcp_getsockopt+0x91/0xf0 __sys_getsockopt+0xf7/0x170 Fix this by wrapping the ca_ops load and get_info call within rcu_read_lock()/rcu_read_unlock(), and using READ_ONCE() to load the icsk_ca_ops pointer.
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

Affected Products

Vendor Product Affected Versions CPE Subscribe
Linux Linux 0baf26b0fcd74bbfcef53c5d5e8bad2b99c8d0d2 ~ 86814e5370068ec2bf0caa6e6d55c3e5bfc6c324 -
Linux Linux 5.6 -

II. Public POCs for CVE-2026-99138

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III. Intelligence Information for CVE-2026-99138

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Patches & Fixes for CVE-2026-99138 (3)

Same Patch Batch · Linux · 2026-10-28 · 117 CVEs total

CVE-2026-99144 sched_ext: Fix use-after-free of a destroyed user DSQ by a deferred reenqueue
CVE-2026-99129 selinux: fix BPF token permission checks
CVE-2026-99130 io_uring/cancel: don't spin on local work the task can't run
CVE-2026-99131 xfs: fix capability check in xfs
CVE-2026-99133 net/iucv: fix the recvmsg window update
CVE-2026-99132 xfs: don't hold buffer locks across sync transaction commit in xfs_sync_sb_buf
CVE-2026-99134 mac802154: fix data race and NULL deref on local->assoc_dev
CVE-2026-99135 dm-integrity: fix infinite loop on discard with large tag size
CVE-2026-99137 cifs: don't update i_size in cifs_do_truncate without a cached handle
CVE-2026-99136 dm-crypt: fix a tiny race condition in crypt_dec_pending
CVE-2026-99140 tracing: Fix hist trigger timestamps for buffered events
CVE-2026-99139 tcp: fix use-after-free in do_tcp_getsockopt(TCP_CONGESTION)
CVE-2026-99141 tracing: Fix crash in print_graph_function_event()
CVE-2026-99142 tracing: Check operator stack capacity before pushing
CVE-2026-99143 tracing: Keep the predicate limit separate from program capacity
CVE-2026-99156 scsi: st: Fix use-after-free race between st_remove() and st_open()
CVE-2026-99153 scsi: libiscsi: Validate the ITT reflected in a Reject PDU
CVE-2026-99152 scsi: libiscsi: Validate the task named by a management response
CVE-2026-99154 scsi: libiscsi: Reject a negative task index from parse_pdu_itt
CVE-2026-99151 drm/amd/display: Fix NULL sink dereference in USB4 bandwidth functions

Showing top 20 of 117 CVEs. View all on vendor page → →

IV. Related Vulnerabilities

Same product: Linux
Same vendor: Linux