Linux: Improper Null Termination
CVE-2026-72095 is a high-severity improper null termination vulnerability in Linux, with a CVSS 3.1 base score of 7.8 out of 10. It can be exploited with local access to the system by an attacker with a low-privileged account, without any action from a user. The record lists versions 7aa8f3dba53422465dbe1be8dbb7240304462bb2, e2d9a2ea178a5da0b4a6693e8ebca5c7fc4d7051, 77a9298741f8f9e8b963c977f5582ab21c6d3427 as the first without the flaw, so updating Linux to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.17% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update Linux to 7aa8f3dba53422465dbe1be8dbb7240304462bb2 or e2d9a2ea178a5da0b4a6693e8ebca5c7fc4d7051 or 77a9298741f8f9e8b963c977f5582ab21c6d3427, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | 575ec9b0c2f11f40535ea737ed5a64792780d1ef up to, but not including, 7aa8f3dba53422465dbe1be8dbb7240304462bb2; 575ec9b0c2f11f40535ea737ed5a64792780d1ef up to, but not including, e2d9a2ea178a5da0b4a6693e8ebca5c7fc4d7051; 575ec9b0c2f11f40535ea737ed5a64792780d1ef up to, but not including, 77a9298741f8f9e8b963c977f5582ab21c6d3427; 6.16 | 7aa8f3dba53422465dbe1be8dbb7240304462bb2, e2d9a2ea178a5da0b4a6693e8ebca5c7fc4d7051, 77a9298741f8f9e8b963c977f5582ab21c6d3427 |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- LocalThe attacker needs local access or must trick a user into running something.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- LowA basic user account is enough.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H. Scored by CNA.
Official description
In the Linux kernel, the following vulnerability has been resolved: dma-fence: Make dma_fence_dedup_array() robust against 0-count input dma_fence_dedup_array() returns 1 when called with num_fences == 0: the for-loop body never executes, j stays at 0, and the final `return ++j` yields 1. This contradicts both the kernel-doc ("Return: Number of unique fences remaining in the array") and the natural expectation that 0 input gives 0 output. The caller __dma_fence_unwrap_merge() bails out via the `if (count == 0 || count == 1)` fast path and so is save. But amdgpu_userq_wait_*() could reach the dedup call with a zero local count and dereference an uninitialized fence slot in the array. Make the contract match the documentation by returning 0 early. This also skips an unnecessary sort() call on an empty array.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Null Termination
The product does not terminate or incorrectly terminates a string or array with a null character or equivalent terminator.
How developers prevent this class of flaw
- Use a language that is not susceptible to these issues. However, be careful of null byte interaction errors (CWE-626) with lower-level constructs that may be written in a language that is susceptible.
- Ensure that all string functions used are understood fully as to how they append null characters. Also, be wary of off-by-one errors when appending nulls to the end of strings.
- If performance constraints permit, special code can be added that validates null-termination of string buffers, this is a rather naive and error-prone solution.
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Other references
Recent Improper Null Termination vulnerabilities
- 8.4 High severity
- 9.8 Critical severity
- 9.8 Critical severity
- 7.1 High severity
- 7.1 High severity
- 7.5 High severity
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