CVE-2026-99096

Description

In the Linux kernel, the following vulnerability has been resolved: io_uring/register: don't exempt disabled rings from task restrictions A ring created with IORING_SETUP_R_DISABLED is exempt from its register restrictions until it is enabled. This lets the creator register the restrictions and then enable the ring with IORING_REGISTER_ENABLE_RINGS, whether or not that opcode is in the allowed set. Since commit ed82f35b926b ("io_uring: allow registration of per-task restrictions"), a ring also inherits restrictions from the task that creates it, and the same exemption applies to those. A task whose register opcodes are restricted can therefore create a disabled ring, issue any register opcode on it, and then enable it. Mark rings whose restrictions were inherited from the task, and keep checking register opcodes for them while the ring is disabled. Enabling such a ring now requires IORING_REGISTER_ENABLE_RINGS to be in the task's allowed set. Per-ring restrictions registered on a disabled ring work as before. [axboe: amend with inheritance flag fixup]

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EPSS — Exploit Prediction

0.0015

Probability of exploitation

0.04%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

References

Other References

https://git.kernel.org/stable/c/6da8f402e362b2f546e2efb7167fc9597aef6faf https://git.kernel.org/stable/c/f55c240192ded562386de843bfa067671d2731d5

Frequently Asked Questions

What is CVE-2026-99096? +

In the Linux kernel, the following vulnerability has been resolved: io_uring/register: don't exempt disabled rings from task restrictions A ring created with IORING_SETUP_R_DISABLED is exempt from its register restrictions until it is enabled. This lets the creator register the restrictions and then enable the ring with IORING_REGISTER_ENABLE_RINGS, whether or not that opcode is in the allowed set. Since commit ed82f35b926b ("io_uring: allow registration of per-task restrictions"), a ring also inherits restrictions from the task that creates it, and the same exemption applies to those. A task whose register opcodes are restricted can therefore create a disabled ring, issue any register opcode on it, and then enable it. Mark rings whose restrictions were inherited from the task, and keep checking register opcodes for them while the ring is disabled. Enabling such a ring now requires IORING_REGISTER_ENABLE_RINGS to be in the task's allowed set. Per-ring restrictions registered on a disabled ring work as before. [axboe: amend with inheritance flag fixup]

How do I check if I'm vulnerable to CVE-2026-99096? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.