CVE-2026-64339 Vulnerability Analysis & Exploit Details

CVE-2026-64339
Vulnerability Scoring

7.1
/10
Very High Risk

Highly exploitable, CVE-2026-64339 poses a critical security risk that could lead to severe breaches.

Attack Complexity Details

  • Attack Complexity: Low
    Exploits can be performed without significant complexity or 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-2026-64339 Details

Status: Analyzed

Last updated: 🕓 03 Sep 2026, 16:02 UTC
Originally published on: 🕙 25 Jul 2026, 10:17 UTC

Time between publication and last update: 40 days

CVSS Release: version 3

CVSS3 Source

nvd@nist.gov

CVSS3 Type

Primary

CVSS3 Vector

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

CVE-2026-64339 Vulnerability Summary

CVE-2026-64339: In the Linux kernel, the following vulnerability has been resolved: usb: misc: usbio: bound bulk IN response length to the received transfer usbio_bulk_msg() copies bpkt_len = le16_to_cpu(bpkt->len) bytes out of the bulk IN buffer (usbio->rxbuf, allocated with size usbio->rxbuf_len) into the caller's buffer. bpkt_len is fully controlled by the device and is only checked against ibuf_len; ibuf_len in turn is checked against usbio->txbuf_len, not against rxbuf_len: if ((obuf_len > (usbio->txbuf_len - sizeof(*bpkt))) || (ibuf_len > (usbio->txbuf_len - sizeof(*bpkt)))) return -EMSGSIZE; txbuf_len and rxbuf_len are taken independently from the bulk OUT and bulk IN endpoint wMaxPacketSize in usbio_probe(). A malicious or malfunctioning device that advertises a large bulk OUT endpoint and a small bulk IN endpoint (e.g. by claiming one of the quirk-free IDs such as the Lattice NX33U, 0x2ac1:0x20cb) therefore makes ibuf_len, and hence the device-supplied bpkt_len, exceed rxbuf_len. memcpy() then reads up to txbuf_len - rxbuf_len bytes past the end of the rxbuf slab object. The over-read bytes are handed back to the i2c layer and on to user space through i2c-dev, disclosing adjacent slab memory; with KASAN this is reported as a slab-out-of-bounds read. The number of bytes actually received is already known: act equals the URB actual_length and is bounded by rxbuf_len. Reject any response that claims more payload than was received, mirroring the existing "act < sizeof(*bpkt)" check just above. The control path (usbio_ctrl_msg()) is not affected: it uses a single buffer (ctrlbuf) for both directions, so its analogous copy can never leave the allocation. Found by code review. The out-of-bounds read was confirmed under AddressSanitizer with a faithful userspace model of usbio_bulk_msg()'s receive path (an rxbuf_len-sized buffer, the same act/ibuf_len/bpkt_len checks and the memcpy). A USB raw-gadget + dummy_hcd reproducer is also available.

Assessing the Risk of CVE-2026-64339

Access Complexity Graph

The exploitability of CVE-2026-64339 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-2026-64339

CVE-2026-64339 presents an accessible attack vector with minimal effort required. Restricting access controls and implementing security updates are critical to reducing exploitation 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-2026-64339, 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-2026-64339, showing how Confidentiality, Integrity, and Availability might be affected if the vulnerability is exploited. Higher values usually signal greater potential damage.

  • Confidentiality: High
    Exploiting CVE-2026-64339 can result in unauthorized access to sensitive data, severely compromising data privacy.
  • Integrity: None
    CVE-2026-64339 poses no threat to data integrity.
  • Availability: High
    CVE-2026-64339 can disrupt system operations, potentially causing complete denial of service (DoS).

CVE-2026-64339 References

External References

CWE Common Weakness Enumeration

CWE-125

CAPEC Common Attack Pattern Enumeration and Classification

  • Overread Buffers CAPEC-540 An adversary attacks a target by providing input that causes an application to read beyond the boundary of a defined buffer. This typically occurs when a value influencing where to start or stop reading is set to reflect positions outside of the valid memory location of the buffer. This type of attack may result in exposure of sensitive information, a system crash, or arbitrary code execution.

Vulnerable Configurations

  • 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:6.18.16:*:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.18.16:*:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.18.17:*:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.18.17:*:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.18.18:*:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.18.18:*:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.18.19:*:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.18.19:*:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.18.20:*:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.18.20:*:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.18.21:*:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.18.21:*:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.18.22:*:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.18.22:*:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.18.23:*:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.18.23:*:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.18.24:*:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.18.24:*:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.18.25:*:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.18.25:*:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.18.26:*:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.18.26:*:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.18.27:*:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.18.27:*:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.18.28:*:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.18.28:*:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.18.29:*:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.18.29:*:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.18.30:*:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.18.30:*:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.18.31:*:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.18.31:*:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.18.32:*:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.18.32:*:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.18.33:*:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.18.33:*:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.18.34:*:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.18.34:*:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.18.35:*:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.18.35:*:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.18.36:*:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.18.36:*:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.18.37:*:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.18.37:*:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.18.38:*:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.18.38:*:*:*:*:*:*:*
  • 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:*:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.19.6:*:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.19.6:*:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.19.7:*:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.19.7:*:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.19.8:*:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.19.8:*:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.19.9:*:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.19.9:*:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.19.10:*:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.19.10:*:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.19.11:*:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.19.11:*:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.19.12:*:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.19.12:*:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.19.13:*:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.19.13:*:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.19.14:*:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.19.14:*:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.19:rc1:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.19:rc1:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.19:rc2:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.19:rc2:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.19:rc3:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.19:rc3:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.19:rc4:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.19:rc4:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.19:rc5:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.19:rc5:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.19:rc6:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.19:rc6:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.19:rc7:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.19:rc7:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.19:rc8:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.19:rc8:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:7.0:-:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:7.0:-:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:7.0.1:*:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:7.0.1:*:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:7.0.2:*:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:7.0.2:*:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:7.0.3:*:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:7.0.3:*:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:7.0.4:*:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:7.0.4:*:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:7.0.5:*:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:7.0.5:*:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:7.0.6:*:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:7.0.6:*:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:7.0.7:*:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:7.0.7:*:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:7.0.8:*:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:7.0.8:*:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:7.0.9:*:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:7.0.9:*:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:7.0.10:*:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:7.0.10:*:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:7.0.11:*:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:7.0.11:*:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:7.0.12:*:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:7.0.12:*:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:7.0.13:*:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:7.0.13:*:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:7.0.14:*:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:7.0.14:*:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:7.0:rc1:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:7.0:rc1:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:7.0:rc2:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:7.0:rc2:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:7.0:rc3:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:7.0:rc3:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:7.0:rc4:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:7.0:rc4:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:7.0:rc5:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:7.0:rc5:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:7.0:rc6:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:7.0:rc6:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:7.0:rc7:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:7.0:rc7:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:7.1:-:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:7.1:-:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:7.1.1:*:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:7.1.1:*:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:7.1.2:*:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:7.1.2:*:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:7.1.3:*:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:7.1.3:*:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:7.2:rc1:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:7.2:rc1:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:7.2:rc2:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:7.2:rc2:*:*:*:*:*:*

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