Linux: Incorrect Calculation
CVE-2026-43321 is a high-severity incorrect calculation 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 7beae54111c34ca63357ef120e115889b915beb5, d1aab1ca576c90192ba961094d51b0be6355a4d6 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 0.15% 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 7beae54111c34ca63357ef120e115889b915beb5 or d1aab1ca576c90192ba961094d51b0be6355a4d6, whichever matches your release line, or a later version.
- Update Linux Kernel to 6.19.6 or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | 493d9e0d608339a32f568504d5fd411a261bb0af up to, but not including, 7beae54111c34ca63357ef120e115889b915beb5; 493d9e0d608339a32f568504d5fd411a261bb0af up to, but not including, d1aab1ca576c90192ba961094d51b0be6355a4d6; 6.19 | 7beae54111c34ca63357ef120e115889b915beb5, d1aab1ca576c90192ba961094d51b0be6355a4d6 |
| Linux | Linux Kernel | 6.19 up to, but not including, 6.19.6; 7.0 | 6.19.6 |
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: bpf: Properly mark live registers for indirect jumps For a `gotox rX` instruction the rX register should be marked as used in the compute_insn_live_regs() function. Fix this.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Incorrect Calculation
The product performs a calculation that generates incorrect or unintended results that are later used in security-critical decisions or resource management.
How developers prevent this class of flaw
- Understand your programming language's underlying representation and how it interacts with numeric calculation. Pay close attention to byte size discrepancies, precision, signed/unsigned distinctions, truncation, conversion and casting between types, not-a-number calculations, and how your language handles numbers that are too large or too small for its underlying representation.
- Perform input validation on any numeric input by ensuring that it is within the expected range. Enforce that the input meets both the minimum and maximum requirements for the expected range.
- Use the appropriate type for the desired action. For example, in C/C++, only use unsigned types for values that could never be negative, such as height, width, or other numbers related to quantity.
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
Patches and release notes
Recent Incorrect Calculation vulnerabilities
- 7.5 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 9.8 Critical severity
- 7.5 High severity
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