VulnerabilityPublished 28 Oct 2026

CVE-2026-99138: Linux kernel · TCP_CC_INFO

Affects Linux kernelSource CVE Database V5

Not known to be exploited · fixed in 86814e5370068ec2bf0caa6e6d55c3e5bfc6c324 : update Linux kernel when convenient.

Data as of 28 Oct 2026, 10:58 UTC

Severity

Unrated

Rated by Threat Radar · CVSS not yet scored by NVD

Patch: Available – fixed in 86814e5370068ec2bf0caa6e6d55c3e5bfc6c324, 385e474086c2e7e29e2dded690be40dc273e20ee, 39aa489e85752f9de214edb0f85e4d578e57af29

Exploitation evidence

Disclosed: evidence found.
CVE published 28 Oct 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade Linux kernel to 86814e5370068ec2bf0caa6e6d55c3e5bfc6c324, 385e474086c2e7e29e2dded690be40dc273e20ee or 39aa489e85752f9de214edb0f85e4d578e57af29.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected ≥ 0baf26b0fcd74bbfcef53c5d5e8bad2b99c8d0d2, < 86814e5370068ec2bf0caa6e6d55c3e5bfc6c324	Fixed in 86814e5370068ec2bf0caa6e6d55c3e5bfc6c324
LinuxLinux	Affected ≥ 0baf26b0fcd74bbfcef53c5d5e8bad2b99c8d0d2, < 385e474086c2e7e29e2dded690be40dc273e20ee	Fixed in 385e474086c2e7e29e2dded690be40dc273e20ee
LinuxLinux	Affected ≥ 0baf26b0fcd74bbfcef53c5d5e8bad2b99c8d0d2, < 39aa489e85752f9de214edb0f85e4d578e57af29	Fixed in 39aa489e85752f9de214edb0f85e4d578e57af29
LinuxLinux	Affected =5.6	Fixed in–

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.

References

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