VulnerabilityPublished 16 Sep 2026Updated 30 Oct 2026

CVE-2026-89996: Linux kernel · dma-buf: dma-heap: don't publish fd before copy_to_user() succeeds

Source GCVE Database

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Authoritative record:CVE-2026-89996· Medium

Not known to be exploited · fixed in ad61defb3e66ac0c598ad6f39b57f15784543d46 : update Linux kernel when convenient.

Data as of 30 Oct 2026, 19:18 UTC

Severity

Medium

Rated Medium by Threat Radar's AI analysis · CVSS not yet scored by NVD

Thin evidence

One scorer or none

Patch: Available – fixed in ad61defb3e66ac0c598ad6f39b57f15784543d46, 1953ef8d11eb5870fe621259708a90900bead272, 69d57dbadb27ffd5eef34fd184bab145500cdabc +3

Exploitation evidence

Disclosed: evidence found.
CVE published 16 Sep 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: 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 30 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.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), 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.

ghsa-cr94-3ppf-3v5m

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected ≥ c02a81fba74fe3488ad6b08bfb5a1329005418f8, < ad61defb3e66ac0c598ad6f39b57f15784543d46	Fixed in ad61defb3e66ac0c598ad6f39b57f15784543d46
LinuxLinux	Affected ≥ c02a81fba74fe3488ad6b08bfb5a1329005418f8, < 1953ef8d11eb5870fe621259708a90900bead272	Fixed in 1953ef8d11eb5870fe621259708a90900bead272
LinuxLinux	Affected ≥ c02a81fba74fe3488ad6b08bfb5a1329005418f8, < 69d57dbadb27ffd5eef34fd184bab145500cdabc	Fixed in 69d57dbadb27ffd5eef34fd184bab145500cdabc
LinuxLinux	Affected ≥ c02a81fba74fe3488ad6b08bfb5a1329005418f8, < 30d0aff2c65a277135cfd8ea28fa1ee75e0ea4e0	Fixed in 30d0aff2c65a277135cfd8ea28fa1ee75e0ea4e0
LinuxLinux	Affected ≥ c02a81fba74fe3488ad6b08bfb5a1329005418f8, < 1bf6083a41f810d760c4dcd1b80c5194a92575aa	Fixed in 1bf6083a41f810d760c4dcd1b80c5194a92575aa
LinuxLinux	Affected ≥ c02a81fba74fe3488ad6b08bfb5a1329005418f8, < 0d4a5d218055db29b50cc07d3d73d27007c2a391	Fixed in 0d4a5d218055db29b50cc07d3d73d27007c2a391

AI-suggested

A fix has been implemented in the Linux kernel that restructures the dma-heap allocation path to prevent fd leaks on copy_to_user() failure. Users should update to a kernel version containing this fix once available. No other mitigation is necessary as the vulnerability is addressed by this official fix.

Description

A vulnerability in the Linux kernel's dma-heap subsystem allowed file descriptors (fd) to be published to other threads before a copy_to_user() operation succeeded, potentially leaking fds and dma-buf references for the lifetime of the process. The flaw was fixed by restructuring the allocation path to ensure the fd is only published after copy_to_user() succeeds, preventing leaks without unsafe close operations.

Impact

If exploited, this vulnerability could cause file descriptor leaks within a process, potentially leading to resource exhaustion or unintended sharing of dma-buf references between threads. However, there is no indication of privilege escalation or direct code execution impact. The vulnerability affects the stability and resource management of processes using dma-heap ioctl allocation.

Summary

The Linux kernel dma-heap ioctl allocation path previously installed a file descriptor into the caller's fd table before copying the fd number back to userspace. If copy_to_user() failed, the fd and underlying dma-buf reference were leaked and visible to other threads in the same process. Attempts to close the fd on failure were unsafe due to possible fd reuse or duplication by other threads. The fix restructured the allocation to reserve an fd number without publishing it, perform copy_to_user(), and only then publish the fd with dma_buf_fd_install(), ensuring no fd leaks occur on failure. This change preserves export tracing and does not alter the UAPI or heap-driver interface.

References

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