CVE-2021-3491 (GCVE-0-2021-3491)

Vulnerability from cvelistv5 – Published: 2021-06-04 01:40 – Updated: 2024-09-16 22:09
VLAI
Title
Linux kernel io_uring PROVIDE_BUFFERS MAX_RW_COUNT bypass
Summary
The io_uring subsystem in the Linux kernel allowed the MAX_RW_COUNT limit to be bypassed in the PROVIDE_BUFFERS operation, which led to negative values being usedin mem_rw when reading /proc/<PID>/mem. This could be used to create a heap overflow leading to arbitrary code execution in the kernel. It was addressed via commit d1f82808877b ("io_uring: truncate lengths larger than MAX_RW_COUNT on provide buffers") (v5.13-rc1) and backported to the stable kernels in v5.12.4, v5.11.21, and v5.10.37. It was introduced in ddf0322db79c ("io_uring: add IORING_OP_PROVIDE_BUFFERS") (v5.7-rc1).
Severity
7.8 (High)
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H
CWE
  • CWE-131 - Incorrect Calculation of Buffer Size
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux kernel Affected: trunk , < v5.13-rc4 (custom)
Affected: linux-5.12.y , < v5.12.4 (custom)
Affected: linux-5.11.y , < v5.11.21 (custom)
Affected: linux-5.10.y , < v5.10.37 (custom)
Affected: v5.7-rc1 , < 5.7* (custom)
guessed Create a notification for this product.
Date Public
2021-05-11 00:00
Credits
Billy Jheng Bing-Jhong (@st424204) of STAR Labs working with Trend Micro's Zero Day Initiative
Show details on NVD website
To clipboard 

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            "source": "nvd@nist.gov",
            "type": "Primary"
          }
        ]
      }
    },
    "redhat_vex": {
      "aggregate_severity": "Important",
      "current_release_date": "2025-11-21T16:15:52+00:00",
      "cve": "CVE-2021-3491",
      "id": "CVE-2021-3491",
      "initial_release_date": "2021-05-11T00:00:00+00:00",
      "product_status:known_not_affected": "196",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: Linux kernel io_uring PROVIDE_BUFFERS MAX_RW_COUNT bypass",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2021/cve-2021-3491.json",
      "version": "3"
    }
  }
}



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Tags
Taxonomy of the tags.





Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

Author Source Type Date Other

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


Detection rules are retrieved from Rulezet.


Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.