CyberSecBulletin
CVE-2026-64018NVD status: Modified

Linux: Improper Validation of Array Index

Published Updated By the CyberSecBulletin desk

CVE-2026-64018 is a critical-severity improper validation of array index vulnerability in Linux, with a CVSS 3.1 base score of 9.3 out of 10. It can be exploited with local access to the system by an unauthenticated attacker, without any action from a user. The record lists versions 5ddc715324badd7f2641bc177db1d027b402adae, ff1d5af207bcea857d45fe81505f1bc4b29eaef0, 01f7f893d5e1baae995beeb86cd0f3e6bb2a3b01 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.

Patch this week

Critical severity: a successful attack would have severe impact.

What to do

  1. Update Linux to 5ddc715324badd7f2641bc177db1d027b402adae or ff1d5af207bcea857d45fe81505f1bc4b29eaef0 or 01f7f893d5e1baae995beeb86cd0f3e6bb2a3b01 or 763a372d344fb12fae566d36ddb46e92454ad58c, whichever matches your release line, or a later version.
  2. Update Linux Kernel to 5.15.209 or 6.1.175 or 6.6.142 or 6.12.92, whichever matches your release line, or a later version.

Affected products and versions

VendorProductAffected versionsFixed in
LinuxLinuxca9c54d2d6a5ab2430c4eda364c77125d62e5e0f up to, but not including, 5ddc715324badd7f2641bc177db1d027b402adae; ca9c54d2d6a5ab2430c4eda364c77125d62e5e0f up to, but not including, ff1d5af207bcea857d45fe81505f1bc4b29eaef0; ca9c54d2d6a5ab2430c4eda364c77125d62e5e0f up to, but not including, 01f7f893d5e1baae995beeb86cd0f3e6bb2a3b01; ca9c54d2d6a5ab2430c4eda364c77125d62e5e0f up to, but not including, 763a372d344fb12fae566d36ddb46e92454ad58c; ca9c54d2d6a5ab2430c4eda364c77125d62e5e0f up to, but not including, fa627a5eaa83fc0261f44ef3769693b886ca6e27; ca9c54d2d6a5ab2430c4eda364c77125d62e5e0f up to, but not including, 355e9f2b2a7887ca38100127989af3e422ba71d0; ca9c54d2d6a5ab2430c4eda364c77125d62e5e0f up to, but not including, b809d0409991b75a6cff846a5ac27c3062953f84; 5.135ddc715324badd7f2641bc177db1d027b402adae, ff1d5af207bcea857d45fe81505f1bc4b29eaef0, 01f7f893d5e1baae995beeb86cd0f3e6bb2a3b01, 763a372d344fb12fae566d36ddb46e92454ad58c, fa627a5eaa83fc0261f44ef3769693b886ca6e27, 355e9f2b2a7887ca38100127989af3e422ba71d0
LinuxLinux Kernel5.13 up to, but not including, 5.15.209; 5.16 up to, but not including, 6.1.175; 6.2 up to, but not including, 6.6.142; 6.7 up to, but not including, 6.12.92; 6.13 up to, but not including, 6.18.34; 6.19 up to, but not including, 7.0.11; 7.15.15.209, 6.1.175, 6.6.142, 6.12.92, 6.18.34, 7.0.11

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
NoneNo account or login is needed.
User interaction
NoneNo action by a victim is required.
Scope
ChangedThe attack can reach beyond the vulnerable component into other systems.
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:N/UI:N/S:C/C:H/I:H/A:H. Scored by CNA.

Official description

In the Linux kernel, the following vulnerability has been resolved: net: mana: validate rx_req_idx to prevent out-of-bounds array access In mana_hwc_rx_event_handler(), rx_req_idx is derived from sge->address in DMA-coherent memory. In Confidential VMs (SEV-SNP/TDX), this memory is shared unencrypted and HW can modify WQE contents at any time. No bounds check exists on rx_req_idx, which can lead to an out-of-bounds access into reqs[]. Add bounds check on rx_req_idx in mana_hwc_rx_event_handler() before using it to index the reqs[] array.

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Improper Validation of Array Index

The product uses untrusted input when calculating or using an array index, but the product does not validate or incorrectly validates the index to ensure the index references a valid position within the array.

How developers prevent this class of flaw

  • Use an input validation framework such as Struts or the OWASP ESAPI Validation API. Note that using a framework does not automatically address all input validation problems; be mindful of weaknesses that could arise from misusing the framework itself (CWE-1173).
  • Use a language that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. For example, Ada allows the programmer to constrain the values of a variable and languages such as Java and Ruby will allow the programmer to handle exceptions when an out-of-bounds index is accessed.
  • Use a CPU and operating system that offers Data Execution Protection (using hardware NX or XD bits) or the equivalent techniques that simulate this feature in software, such as PaX. These techniques ensure that any instruction executed is exclusively at a memory address that is part of the code segment. For more information on these techniques see D3-PSEP (Process Segment Execution Prevention) from D3FEND.

More Improper Validation of Array Index vulnerabilities (CWE-129)

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 Improper Validation of Array Index vulnerabilities

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