Unscored severity · published Oct 28, 2026
CVE-2026-99138
tcp: fix use-after-free in do_tcp_getsockopt(TCP_CC_INFO)
New
–
CVSS
–
EPSS
No
On KEV
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.
Exploitation
Is it being used?
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
LI
Linux · Linux
0baf26b0fcd74bbfcef53c5d5e8bad2b99c8d0d2 before 86814e5370068ec2bf0caa6e6d55c3e5bfc6c324; 0baf26b0fcd74bbfcef53c5d5e8bad2b99c8d0d2 before 39aa489e85752f9de214edb0f85e4d578e57af29; 0baf26b0fcd74bbfcef53c5d5e8bad2b99c8d0d2 before 385e474086c2e7e29e2dded690be40dc273e20ee; 5.6 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-99138
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-99138
git.kernel.org
https://git.kernel.org/stable/c/86814e5370068ec2bf0caa6e6d55c3e5bfc6c324
git.kernel.org
https://git.kernel.org/stable/c/39aa489e85752f9de214edb0f85e4d578e57af29
git.kernel.org
https://git.kernel.org/stable/c/385e474086c2e7e29e2dded690be40dc273e20ee
More from Linux
9.8
CVE-2025-39682
tls: fix handling of zero-length records on the rx_list
8.8
CVE-2026-53266
netfilter: bridge: make ebt_snat ARP rewrite writable
7.8
CVE-2026-53362
ipv6: account for fraggap on the paged allocation path
7.8
CVE-2026-31431
crypto: algif_aead - Revert to operating out-of-place
7.8
CVE-2025-38352
posix-cpu-timers: fix race between handle_posix_cpu_timers() and posix_cpu_timer_del()
