Quick answers
- Is CVE-2026-99288 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-99288 being exploited in the wild.
- How severe is CVE-2026-99288?
- Informational severity, published 10 November 2026.
- Which products and versions are affected?
- Linux Kernel before fix.
- Is there a fix for CVE-2026-99288?
- No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
- How is CVE-2026-99288 attacked?
- It is attacked over the network, in an operating system.
- Am I affected by CVE-2026-99288?
- Check whether you run Linux Kernel at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.
Technical details
The vulnerability exists in inet_lookup_established() and inet6_lookup_established() functions which perform lockless lookups using SLAB_TYPESAFE_BY_RCU allocated sockets. Memory reuse before RCU readers finish can lead to dereferencing unhashed sockets, causing a null pointer dereference when the code accesses sk_state through a NULL listener in tcp_v4_rcv(). The fix adds validation to check whether the nulls node is hashed after taking a reference and before returning the socket.
Affected products
- Linux Linux kernel before fix
Timeline
- 2026-11-10: disclosed