CVE-2026-43121 Vulnerability Analysis & Exploit Details

CVE-2026-43121
Vulnerability Scoring

4.7
/10
Medium Risk

The vulnerability CVE-2026-43121 could compromise system integrity but typically requires user interaction to be exploited.

Attack Complexity Details

  • Attack Complexity: High
    Exploits require significant effort and special conditions.
  • Attack Vector: Local
    Vulnerability requires local system access.
  • Privileges Required: Low
    Some privileges are necessary to exploit the vulnerability.
  • Scope: Unchanged
    Exploit remains within the originally vulnerable component.
  • User Interaction: None
    No user interaction is necessary for exploitation.

CVE-2026-43121 Details

Status: Analyzed

Last updated: 🕘 12 May 2026, 21:17 UTC
Originally published on: 🕛 06 May 2026, 12:16 UTC

Time between publication and last update: 6 days

CVSS Release: version 3

CVSS3 Source

nvd@nist.gov

CVSS3 Type

Primary

CVSS3 Vector

CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H

CVE-2026-43121 Vulnerability Summary

CVE-2026-43121: In the Linux kernel, the following vulnerability has been resolved: io_uring/zcrx: fix user_ref race between scrub and refill paths The io_zcrx_put_niov_uref() function uses a non-atomic check-then-decrement pattern (atomic_read followed by separate atomic_dec) to manipulate user_refs. This is serialized against other callers by rq_lock, but io_zcrx_scrub() modifies the same counter with atomic_xchg() WITHOUT holding rq_lock. On SMP systems, the following race exists: CPU0 (refill, holds rq_lock) CPU1 (scrub, no rq_lock) put_niov_uref: atomic_read(uref) - 1 // window opens atomic_xchg(uref, 0) - 1 return_niov_freelist(niov) [PUSH #1] // window closes atomic_dec(uref) - wraps to -1 returns true return_niov(niov) return_niov_freelist(niov) [PUSH #2: DOUBLE-FREE] The same niov is pushed to the freelist twice, causing free_count to exceed nr_iovs. Subsequent freelist pushes then perform an out-of-bounds write (a u32 value) past the kvmalloc'd freelist array into the adjacent slab object. Fix this by replacing the non-atomic read-then-dec in io_zcrx_put_niov_uref() with an atomic_try_cmpxchg loop that atomically tests and decrements user_refs. This makes the operation safe against concurrent atomic_xchg from scrub without requiring scrub to acquire rq_lock. [pavel: removed a warning and a comment]

Assessing the Risk of CVE-2026-43121

Access Complexity Graph

The exploitability of CVE-2026-43121 depends on two key factors: attack complexity (the level of effort required to execute an exploit) and privileges required (the access level an attacker needs).

Exploitability Analysis for CVE-2026-43121

This vulnerability, CVE-2026-43121, requires a high level of attack complexity and low privileges, making it difficult but not impossible to exploit. Organizations should ensure robust security configurations to mitigate risks.

Understanding AC and PR

A lower complexity and fewer privilege requirements make exploitation easier. Security teams should evaluate these aspects to determine the urgency of mitigation strategies, such as patch management and access control policies.

Attack Complexity (AC) measures the difficulty in executing an exploit. A high AC means that specific conditions must be met, making an attack more challenging, while a low AC means the vulnerability can be exploited with minimal effort.

Privileges Required (PR) determine the level of system access necessary for an attack. Vulnerabilities requiring no privileges are more accessible to attackers, whereas high privilege requirements limit exploitation to authorized users with elevated access.

CVSS Score Breakdown Chart

Above is the CVSS Sub-score Breakdown for CVE-2026-43121, illustrating how Base, Impact, and Exploitability factors combine to form the overall severity rating. A higher sub-score typically indicates a more severe or easier-to-exploit vulnerability.

CIA Impact Analysis

Below is the Impact Analysis for CVE-2026-43121, showing how Confidentiality, Integrity, and Availability might be affected if the vulnerability is exploited. Higher values usually signal greater potential damage.

  • Confidentiality: None
    CVE-2026-43121 has no significant impact on data confidentiality.
  • Integrity: None
    CVE-2026-43121 poses no threat to data integrity.
  • Availability: High
    CVE-2026-43121 can disrupt system operations, potentially causing complete denial of service (DoS).

CVE-2026-43121 References

External References

CWE Common Weakness Enumeration

CWE-362

CAPEC Common Attack Pattern Enumeration and Classification

  • Leveraging Race Conditions CAPEC-26 The adversary targets a race condition occurring when multiple processes access and manipulate the same resource concurrently, and the outcome of the execution depends on the particular order in which the access takes place. The adversary can leverage a race condition by "running the race", modifying the resource and modifying the normal execution flow. For instance, a race condition can occur while accessing a file: the adversary can trick the system by replacing the original file with their version and cause the system to read the malicious file.
  • Leveraging Time-of-Check and Time-of-Use (TOCTOU) Race Conditions CAPEC-29 This attack targets a race condition occurring between the time of check (state) for a resource and the time of use of a resource. A typical example is file access. The adversary can leverage a file access race condition by "running the race", meaning that they would modify the resource between the first time the target program accesses the file and the time the target program uses the file. During that period of time, the adversary could replace or modify the file, causing the application to behave unexpectedly.

Vulnerable Configurations

  • cpe:2.3:o:linux:linux_kernel:6.15:-:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.15:-:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.15.1:*:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.15.1:*:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.15.2:*:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.15.2:*:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.15.3:*:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.15.3:*:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.15.4:*:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.15.4:*:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.15.5:*:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.15.5:*:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.15.6:*:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.15.6:*:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.15.7:*:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.15.7:*:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.15.8:*:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.15.8:*:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.15.9:*:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.15.9:*:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.15.10:*:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.15.10:*:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.15.11:*:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.15.11:*:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.15:rc1:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.15:rc1:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.15:rc2:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.15:rc2:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.15:rc3:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.15:rc3:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.15:rc4:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.15:rc4:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.15:rc5:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.15:rc5:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.15:rc6:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.15:rc6:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.15:rc7:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.15:rc7:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.16:-:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.16:-:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.16.1:*:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.16.1:*:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.16.2:*:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.16.2:*:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.16.3:*:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.16.3:*:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.16.4:*:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.16.4:*:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.16.5:*:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.16.5:*:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.16.6:*:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.16.6:*:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.16.7:*:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.16.7:*:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.16.8:*:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.16.8:*:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.16.9:*:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.16.9:*:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.16.10:*:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.16.10:*:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.16.11:*:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.16.11:*:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.16.12:*:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.16.12:*:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.16:rc1:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.16:rc1:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.16:rc2:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.16:rc2:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.16:rc3:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.16:rc3:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.16:rc4:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.16:rc4:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.16:rc5:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.16:rc5:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.16:rc6:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.16:rc6:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.16:rc7:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.16:rc7:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.17:-:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.17:-:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.17.1:*:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.17.1:*:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.17.2:*:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.17.2:*:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.17.3:*:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.17.3:*:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.17.4:*:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.17.4:*:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.17.5:*:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.17.5:*:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.17.6:*:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.17.6:*:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.17.7:*:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.17.7:*:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.17.8:*:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.17.8:*:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.17.9:*:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.17.9:*:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.17.10:*:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.17.10:*:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.17.11:*:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.17.11:*:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.17.12:*:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.17.12:*:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.17.13:*:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.17.13:*:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.17:rc1:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.17:rc1:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.17:rc2:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.17:rc2:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.17:rc3:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.17:rc3:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.17:rc4:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.17:rc4:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.17:rc5:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.17:rc5:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.17:rc6:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.17:rc6:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.17:rc7:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.17:rc7:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.18:-:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.18:-:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.18.1:*:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.18.1:*:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.18.2:*:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.18.2:*:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.18.3:*:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.18.3:*:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.18.4:*:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.18.4:*:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.18.5:*:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.18.5:*:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.18.6:*:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.18.6:*:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.18.7:*:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.18.7:*:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.18.8:*:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.18.8:*:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.18.9:*:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.18.9:*:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.18.10:*:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.18.10:*:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.18.11:*:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.18.11:*:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.18.13:*:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.18.13:*:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.18.14:*:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.18.14:*:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.19:-:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.19:-:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.19.1:*:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.19.1:*:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.19.3:*:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.19.3:*:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.19.4:*:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.19.4:*:*:*:*:*:*:*

Protect Your Infrastructure against CVE-2026-43121: Combat Critical CVE Threats

Stay updated with real-time CVE vulnerabilities and take action to secure your systems. Enhance your cybersecurity posture with the latest threat intelligence and mitigation techniques. Develop the skills necessary to defend against CVEs and secure critical infrastructures. Join the top cybersecurity professionals safeguarding today's infrastructures.

Other 5 Recently Published CVEs Vulnerabilities

  • CVE-2026-9730 – The Remove NoFollow Commenter URL plugin for WordPress is vulnerable to Cross-Site Request Forgery in all versions up to, and including, 1.0. This ...
  • CVE-2026-9723 – The Google Plus One Bottom plugin for WordPress is vulnerable to Cross-Site Request Forgery in all versions up to, and including, 0.0.2. This is du...
  • CVE-2026-9722 – The Laiser Tag plugin for WordPress is vulnerable to Cross-Site Request Forgery in all versions up to, and including, 1.2.5. This is due to missing...
  • CVE-2026-9599 – The Tectite Forms plugin for WordPress is vulnerable to Cross-Site Request Forgery in all versions up to, and including, 1.3. This is due to missin...
  • CVE-2026-9234 – The JTL-Connector for WooCommerce plugin for WordPress is vulnerable to Missing Authorization in versions up to, and including, 2.4.1. This is due ...