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CVE-2026-99096

io_uring/register: don't exempt disabled rings from task restrictions

CVSS score

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EPSS probability

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Risk score

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Published

4 h ago

OverviewPublic Exploits (0)NewsroomVulnerability Timeline
Patch status has not yet been verified

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Vulnerability description

DayBreach AI Explanation

Verified against sources

CVE-2026-99096: Linux Kernel io_uring Task Restriction Bypass Vulnerability

Sources read

1

Source agreement

Tam uyum

Evidence confidence

%55

Short explanation

A vulnerability exists in the Linux kernel io_uring subsystem where disabled rings are exempt from task restrictions. This flaw allows a creator with restricted register opcodes to create a disabled ring, issue any register opcode on it, and subsequently enable it.

Why does it matter?

Users with restricted tasks can bypass existing register constraints due to this logic flaw in the io_uring component, potentially allowing unauthorized register operations to be performed.

What should be done?

  • Follow vendor advisories for relevant Linux kernel updates and patch notices.
  • Apply the corresponding commit fixes in the kernel source code.
Chain of evidence and sources2 verified claims

IORING_SETUP_R_DISABLED ile oluşturulan halkalar, etkinleştirilene kadar kayıt kısıtlamalarından muaf tutulmaktadır.

S0 · daybreach-canonicalS1 · cvelist

Kısıtlanmış bir görev, devre dışı bırakılmış bir halka oluşturarak bu halka üzerinde herhangi bir kayıt işlem kodu çalıştırabilir ve ardından halkayı etkinleştirebilir.

S0 · daybreach-canonicalS1 · cvelist
Show the technical text from the sources

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]

This explanation was compiled automatically from the source records. Scores, active exploitation, patch and exploit status come straight from the sources.

IMPACT: Affected Products and Software

Affected Products

The following products are affected by CVE-2026-99096 vulnerability. Where our threat engine knows the exact affected versions, they are listed below.

IDVENDORPRODUCTACTION
1linuxLinux View
2linuxLinux View
Total affected vendors: 1|Products: 2

RED HAT CSAF/VEX: Product Impact Check

Red Hat has not yet published a CSAF/VEX impact record for this CVE. This does not mean “not affected”.

SCORING: CVSS from Multiple Sources

CVSS Scores

The Common Vulnerability Scoring System is a standardised framework for assessing the severity of vulnerabilities in software and systems. We collect and display CVSS scores from several sources for each CVE.

SCOREVERSIONSEVERITYVECTORSOURCE
The sources have not yet published a verified CVSS metric.

Patch and Remediation Guide

Solution & Remediation Advisory

Patch status unknown

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Confirm the affected product and version against the source evidence above.
Restrict access to internet-facing services and apply network segmentation.
Until a patch is confirmed, follow the vendor advisory; do not read an unknown status as “no patch”.
Monitor server logs and network endpoints for signs of anomalous execution.

Public exploit and active exploitation status

Verified exploit intelligence

No verified public PoC, exploit repository or Metasploit module has been found for this CVE yet.

Weakness Classification and Attack Patterns (CWE & CAPEC)

CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorises the common flaws or weaknesses that can lead to vulnerabilities. CVE-2026-99096 is associated with the following CWEs:

CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')CWE-20: Improper Input Validation

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2026-99096 weaknesses.

CAPEC-66: SQL InjectionCAPEC-126: Path TraversalCAPEC-28: OS Command Injection

Official Sources and Advisories

https://git.kernel.org/stable/c/f55c240192ded562386de843bfa067671d2731d5vendor-advisoryhttps://git.kernel.org/stable/c/6da8f402e362b2f546e2efb7167fc9597aef6fafvendor-advisory

Yama durumu bilinmiyor

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CVE-2026-99096 · io_uring/register: don't exempt disabled…