VulnerabilityPublished 26 Oct 2026Updated 28 Oct 2026

CVE-2026-99097: Linux kernel · tee: shm: reject zero-sized allocations in tee_dyn_shm_alloc_helper()

Affects Linux kernelSource GCVE Database

Authoritative record:CVE-2026-99097· High

Not known to be exploited.

Data as of 29 Oct 2026, 00:58 UTC

Severity

High

Rated by Threat Radar · CVSS not yet scored by NVD

Exploitation evidence

Disclosed: evidence found.
CVE published 26 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

Affected software

Product	Affected	Fixed in
Ubuntu 26.10linux`pkg:deb/ubuntu/linux?arch=source&distro=stonking`Other threats	Affected 7.0.0-14.14 – 7.3.0-9.9 6 affected builds	Fixed in–
Ubuntu 26.10linux-aws`pkg:deb/ubuntu/linux-aws?arch=source&distro=stonking`Other threats	Affected 7.0.0-1004.4 – 7.3.0-1003.3 5 affected builds	Fixed in–
Ubuntu 26.10linux-azure`pkg:deb/ubuntu/linux-azure?arch=source&distro=stonking`Other threats	Affected 7.0.0-1004.4 – 7.3.0-1003.3 5 affected builds	Fixed in–
Ubuntu 26.10linux-azure-fde`pkg:deb/ubuntu/linux-azure-fde?arch=source&distro=stonking`Other threats	Affected =7.0.0-1004.4 =7.3.0-1002.3 =7.3.0-1003.4	Fixed in–
Ubuntu 26.10linux-gcp`pkg:deb/ubuntu/linux-gcp?arch=source&distro=stonking`Other threats	Affected 7.0.0-1003.3 – 7.3.0-1003.3 5 affected builds	Fixed in–
Ubuntu 26.10linux-oracle`pkg:deb/ubuntu/linux-oracle?arch=source&distro=stonking`Other threats	Affected 7.0.0-1003.3 – 7.3.0-1003.3 5 affected builds	Fixed in–

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

A fix has been implemented that rejects zero-sized allocations in tee_dyn_shm_alloc_helper(). Systems should apply the official kernel updates that include this fix. No additional mitigation is required if the system is updated. For unpatched systems, avoid triggering the TEE_IOC_SHM_ALLOC ioctl with zero size parameters.

Description

A vulnerability in the Linux kernel's TEE subsystem allows zero-sized shared memory allocations via tee_dyn_shm_alloc_helper(). This occurs because the function does not check for zero size before calculating pages, leading to an invalid allocation request that can trigger kernel warnings and potentially cause a kernel panic during boot on systems with panic_on_warn enabled. The flaw is triggered by the TEE_IOC_SHM_ALLOC ioctl with a zero size parameter. The issue has been resolved by rejecting zero-sized allocations.

Impact

The vulnerability can cause kernel allocation failures and potentially a kernel panic during system boot on kernels configured with panic_on_warn. This can lead to denial of service by preventing the system from booting properly. There is no indication of privilege escalation or code execution. No known exploits are reported in the wild.

Summary

The Linux kernel's tee_dyn_shm_alloc_helper() function calculates the number of pages to allocate from a caller-supplied size without validating that the size is non-zero. When size is zero, the derived page count is zero, which causes alloc_pages_exact(0) to call get_order(0). This call is undefined and returns a large order value, triggering the page allocator's order > MAX_PAGE_ORDER warning and causing allocation failure. On kernels configured with panic_on_warn, this leads to a kernel panic during boot. The vulnerability can be exploited by invoking the TEE_IOC_SHM_ALLOC ioctl with a struct tee_ioctl_shm_alloc_data where size is zero. The fix involves rejecting zero-sized allocations in tee_dyn_shm_alloc_helper(), consistent with existing checks in register_shm_helper().

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 29 Oct 2026, 00:58 UTC

Technical details

References

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