Quick answers
- Is CVE-2026-99283 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-99283 being exploited in the wild.
- How severe is CVE-2026-99283?
- Informational severity, published 7 November 2026.
- Which products and versions are affected?
- Linux Kernel versions prior to the fix commit.
- Is there a fix for CVE-2026-99283?
- 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-2026-99283 attacked?
- It is attacked over the network, in an operating system.
- Am I affected by CVE-2026-99283?
- 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 netfilter conntrack TCP module incorrectly applies a CLOSE timeout to RST packets that do not match the exact expected sequence number, even when the connection remains in ESTABLISHED state. This causes a 10-second expiration window to trigger prematurely when multiple non-exact RSTs arrive during TCP challenge-ACK rate limiting. The fix applies the UNACK timeout instead for RSTs that leave conntrack in ESTABLISHED state, avoiding premature expiration while preserving normal CLOSE timeouts for RSTs that successfully close the flow.
Affected products
- Linux Linux kernel versions prior to the fix commit
Timeline
- 2026-11-07: disclosed