CyberSecBulletin
CVE-2026-43033NVD status: Modified

Linux: Incorrect Calculation

Published Updated By the CyberSecBulletin desk

CVE-2026-43033 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 8c62f618576519dbed6816fafc623ce592953025, d589abd8b019b07075fda255ceab8c8e950cdb3f, 5466e7d0cd9e4f9cef9d8f18f18b60e7bc1c77e5 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 0.14% chance of exploitation within 30 days, which is low compared with other CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Update Linux to 8c62f618576519dbed6816fafc623ce592953025 or d589abd8b019b07075fda255ceab8c8e950cdb3f or 5466e7d0cd9e4f9cef9d8f18f18b60e7bc1c77e5 or d0c4ff6812386880f30bc64c2921299cc4d7b47f, whichever matches your release line, or a later version.
  2. Update Linux Kernel to 5.10.254 or 5.15.204 or 6.1.170 or 6.6.137, whichever matches your release line, or a later version.

Affected products and versions

VendorProductAffected versionsFixed in
LinuxLinux104880a6b470958ddc30e139c41aa4f6ed3a5234 up to, but not including, 8c62f618576519dbed6816fafc623ce592953025; 104880a6b470958ddc30e139c41aa4f6ed3a5234 up to, but not including, d589abd8b019b07075fda255ceab8c8e950cdb3f; 104880a6b470958ddc30e139c41aa4f6ed3a5234 up to, but not including, 5466e7d0cd9e4f9cef9d8f18f18b60e7bc1c77e5; 104880a6b470958ddc30e139c41aa4f6ed3a5234 up to, but not including, d0c4ff6812386880f30bc64c2921299cc4d7b47f; 104880a6b470958ddc30e139c41aa4f6ed3a5234 up to, but not including, 89fe118b6470119b20c04afc36e45b81a69ea11f; 104880a6b470958ddc30e139c41aa4f6ed3a5234 up to, but not including, 153d5520c3f9fd62e71c7e7f9e34b59cf411e555; 104880a6b470958ddc30e139c41aa4f6ed3a5234 up to, but not including, cded4002d22177e8deaca1f257ecd932c9582b6b; 104880a6b470958ddc30e139c41aa4f6ed3a5234 up to, but not including, e02494114ebf7c8b42777c6cd6982f113bfdbec7; and 1 more ranges8c62f618576519dbed6816fafc623ce592953025, d589abd8b019b07075fda255ceab8c8e950cdb3f, 5466e7d0cd9e4f9cef9d8f18f18b60e7bc1c77e5, d0c4ff6812386880f30bc64c2921299cc4d7b47f, 89fe118b6470119b20c04afc36e45b81a69ea11f, 153d5520c3f9fd62e71c7e7f9e34b59cf411e555
SiemensSIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AB0)V3.1.6 and later; V3.1.5 and later; V3.1.7 and laterNot stated
SiemensSIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AC0)V3.1.6 and later; V3.1.5 and later; V3.1.7 and laterNot stated
SiemensSIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AB0)V3.1.6 and later; V3.1.5 and later; V3.1.7 and laterNot stated
SiemensSIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AC0)V3.1.6 and later; V3.1.5 and later; V3.1.7 and laterNot stated
SiemensSIPLUS S7-1500 CPU 1518-4 PN/DP MFP (6AG1518-4AX00-4AC0)V3.1.6 and later; V3.1.5 and later; V3.1.7 and laterNot stated
LinuxLinux Kernel4.3 up to, but not including, 5.10.254; 5.11 up to, but not including, 5.15.204; 5.16 up to, but not including, 6.1.170; 6.2 up to, but not including, 6.6.137; 6.7 up to, but not including, 6.12.85; 6.13 up to, but not including, 6.18.22; 6.19 up to, but not including, 6.19.12; 7.05.10.254, 5.15.204, 6.1.170, 6.6.137, 6.12.85, 6.18.22

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: crypto: authencesn - Do not place hiseq at end of dst for out-of-place decryption When decrypting data that is not in-place (src != dst), there is no need to save the high-order sequence bits in dst as it could simply be re-copied from the source. However, the data to be hashed need to be rearranged accordingly. Thanks,

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.

More Incorrect Calculation vulnerabilities (CWE-682)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
  3. Record last changed materially (score, affected products, status or references).

References

Recent Incorrect Calculation vulnerabilities

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