Strix
73.2K

CVE-2026-99139

UnknownEPSS 0.17%

Last modified

CVE-2026-99139 is a vulnerability of currently unknown severity. In the Linux kernel, the following vulnerability has been resolved: tcp: fix use-after-free in do_tcp_getsockopt(TCP_CONGESTION) do_tcp_getsockopt() reads icsk->icsk_ca_ops->name without holding rcu_read_lock(). Since commit 0baf26b0fcd7 ("bpf: tcp: Support tcp_congestion_ops in bpf"), icsk_ca_ops can point to dynamically allocated BPF struct_ops memory that may be freed concurrently via setsockopt(TCP_CONGESTION), leading to a use-after-free. BUG: KASAN: slab-use-after-free in _copy_to_user+0x37/0x60 Read of size 16 at addr ffff888013505260 by task exploit/149 _copy_to_user+0x37/0x60 do_tcp_getsockopt+0x158a/0x2460 (net/ipv4/tcp.c:4585) tcp_getsockopt+0x91/0xf0 __sys_getsockopt+0xf7/0x170 Fix this by holding rcu_read_lock() around the ca_ops->name access, using READ_ONCE() to load icsk_ca_ops, and copying the name to a stack buffer before releasing the lock. EPSS estimates a 0.17% chance of exploitation in the next 30 days.

Description

In the Linux kernel, the following vulnerability has been resolved: tcp: fix use-after-free in do_tcp_getsockopt(TCP_CONGESTION) do_tcp_getsockopt() reads icsk->icsk_ca_ops->name without holding rcu_read_lock(). Since commit 0baf26b0fcd7 ("bpf: tcp: Support tcp_congestion_ops in bpf"), icsk_ca_ops can point to dynamically allocated BPF struct_ops memory that may be freed concurrently via setsockopt(TCP_CONGESTION), leading to a use-after-free. BUG: KASAN: slab-use-after-free in _copy_to_user+0x37/0x60 Read of size 16 at addr ffff888013505260 by task exploit/149 _copy_to_user+0x37/0x60 do_tcp_getsockopt+0x158a/0x2460 (net/ipv4/tcp.c:4585) tcp_getsockopt+0x91/0xf0 __sys_getsockopt+0xf7/0x170 Fix this by holding rcu_read_lock() around the ca_ops->name access, using READ_ONCE() to load icsk_ca_ops, and copying the name to a stack buffer before releasing the lock. Also annotate the relevant icsk_ca_ops stores with WRITE_ONCE() to fix the accompanying KCSAN data-race issue.

Metrics

EPSS Probability
0.17%

5.9th percentile

Probability of exploitation in the next 30 days. Learn more

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

VendorProductVersions
LinuxLinux>= 0baf26b0fcd74bbfcef53c5d5e8bad2b99c8d0d2, < a60e62705c17534d6b6539de7b3a40c259e6827f; >= 0baf26b0fcd74bbfcef53c5d5e8bad2b99c8d0d2, < 4b0930d66dde0a1d1898f0edbbb5496c4dfa5f03; >= 0baf26b0fcd74bbfcef53c5d5e8bad2b99c8d0d2, < 08dc5c62c09653d1c4ba67a009beb138486c2604; >= 0baf26b0fcd74bbfcef53c5d5e8bad2b99c8d0d2, < c1804ef016392dd91267d2207ee43b1de34302ca; >= 0baf26b0fcd74bbfcef53c5d5e8bad2b99c8d0d2, < a8e45471afa230c1431c26c8e99ec24377e3b514; >= 0baf26b0fcd74bbfcef53c5d5e8bad2b99c8d0d2, < 5271b79b7ad68dcb222e893773f92bdabf7750f3
LinuxLinux5.6

References

Timeline

Published
Last Modified
Status
Received

Frequently Asked Questions

What is CVE-2026-99139?
In the Linux kernel, the following vulnerability has been resolved: tcp: fix use-after-free in do_tcp_getsockopt(TCP_CONGESTION) do_tcp_getsockopt() reads icsk->icsk_ca_ops->name without holding rcu_read_lock(). Since commit 0baf26b0fcd7 ("bpf: tcp: Support tcp_congestion_ops in bpf"), icsk_ca_ops can point to dynamically allocated BPF struct_ops memory that may be freed concurrently via setsockopt(TCP_CONGESTION), leading to a use-after-free. BUG: KASAN: slab-use-after-free in _copy_to_user+0x37/0x60 Read of size 16 at addr ffff888013505260 by task exploit/149 _copy_to_user+0x37/0x60 do_tcp_getsockopt+0x158a/0x2460 (net/ipv4/tcp.c:4585) tcp_getsockopt+0x91/0xf0 __sys_getsockopt+0xf7/0x170 Fix this by holding rcu_read_lock() around the ca_ops->name access, using READ_ONCE() to load icsk_ca_ops, and copying the name to a stack buffer before releasing the lock. Also annotate the relevant icsk_ca_ops stores with WRITE_ONCE() to fix the accompanying KCSAN data-race issue.
How severe is CVE-2026-99139?
Severity scoring for CVE-2026-99139 is pending analysis. The EPSS model estimates a 0.17% probability of exploitation in the next 30 days.
How do I fix CVE-2026-99139?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

How Strix Helps

Related CVEs from 2026

View all 2026CVEs →

Are you affected by CVE-2026-99139?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST