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Vulnerability · Published Jul 25, 2026 · Assigned by Linux

CVE-2026-64327usb: gadget: f_fs: Initialize epfile->in early to fix endpoint direction checks

Medium 5.5

In plain English

A medium-severity security flaw in Linux from Linux. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 5% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS NVD)5.5Medium
Exploit odds (30 days)0.2%top 94.9% of all CVEs
Exploited in the wildNo reportsnot in CISA KEV
Attack toolingNoneno public tooling known

Official description

In the Linux kernel, the following vulnerability has been resolved: usb: gadget: f_fs: Initialize epfile->in early to fix endpoint direction checks When parsing endpoint descriptors, ffs_data_got_descs() generates the eps_addrmap which contains the endpoint direction. However, epfile->in was previously only populated in ffs_func_eps_enable() which executes upon USB host connection. As a result, early userspace ioctls like FUNCTIONFS_DMABUF_ATTACH that run before the host connects would see epfile->in as 0, leading to incorrect DMA directions. By moving the initialization to ffs_epfiles_create(), epfile->in is accurate before userspace opens the endpoint files.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Debian:13linux6.12.96-1DEBIAN-CVE-2026-64327
Debian:14linux7.1.4-1DEBIAN-CVE-2026-64327
Debian:12linux-6.126.12.100-1~deb12u1DEBIAN-CVE-2026-64327
Ubuntu:26.04:LTSlinux7.0.0-31.31UBUNTU-CVE-2026-64327
Ubuntu:22.04:LTSlinux-allwinner-5.19no fix listedUBUNTU-CVE-2026-64327
Ubuntu:26.04:LTSlinux-aws7.0.0-1012.12UBUNTU-CVE-2026-64327
Ubuntu:22.04:LTSlinux-aws-5.19no fix listedUBUNTU-CVE-2026-64327
Ubuntu:24.04:LTSlinux-aws-6.14no fix listedUBUNTU-CVE-2026-64327
Ubuntu:24.04:LTSlinux-aws-6.17no fix listedUBUNTU-CVE-2026-64327
Ubuntu:22.04:LTSlinux-aws-6.2no fix listedUBUNTU-CVE-2026-64327
Ubuntu:22.04:LTSlinux-aws-6.5no fix listedUBUNTU-CVE-2026-64327
Ubuntu:24.04:LTSlinux-aws-7.07.0.0-1012.12~24.04.1UBUNTU-CVE-2026-64327
Ubuntu:26.04:LTSlinux-azure7.0.0-1014.14UBUNTU-CVE-2026-64327
Ubuntu:22.04:LTSlinux-azure-5.19no fix listedUBUNTU-CVE-2026-64327
Ubuntu:24.04:LTSlinux-azure-6.11no fix listedUBUNTU-CVE-2026-64327
Ubuntu:24.04:LTSlinux-azure-6.14no fix listedUBUNTU-CVE-2026-64327
Ubuntu:24.04:LTSlinux-azure-6.17no fix listedUBUNTU-CVE-2026-64327
Ubuntu:22.04:LTSlinux-azure-6.2no fix listedUBUNTU-CVE-2026-64327
Ubuntu:22.04:LTSlinux-azure-6.5no fix listedUBUNTU-CVE-2026-64327
Ubuntu:24.04:LTSlinux-azure-7.07.0.0-1014.14~24.04.1UBUNTU-CVE-2026-64327
Ubuntu:26.04:LTSlinux-azure-fde7.0.0-1013.13UBUNTU-CVE-2026-64327
Ubuntu:22.04:LTSlinux-azure-fde-5.19no fix listedUBUNTU-CVE-2026-64327
Ubuntu:24.04:LTSlinux-azure-fde-6.14no fix listedUBUNTU-CVE-2026-64327
Ubuntu:22.04:LTSlinux-azure-fde-6.2no fix listedUBUNTU-CVE-2026-64327
Ubuntu:24.04:LTSlinux-azure-fde-7.07.0.0-1013.13~24.04.1UBUNTU-CVE-2026-64327
Ubuntu:24.04:LTSlinux-azure-nvidia-6.14no fix listedUBUNTU-CVE-2026-64327
Ubuntu:26.04:LTSlinux-gcp7.0.0-1011.11UBUNTU-CVE-2026-64327
Ubuntu:22.04:LTSlinux-gcp-5.19no fix listedUBUNTU-CVE-2026-64327
Ubuntu:24.04:LTSlinux-gcp-6.11no fix listedUBUNTU-CVE-2026-64327
Ubuntu:24.04:LTSlinux-gcp-6.14no fix listedUBUNTU-CVE-2026-64327
Ubuntu:24.04:LTSlinux-gcp-6.17no fix listedUBUNTU-CVE-2026-64327
Ubuntu:22.04:LTSlinux-gcp-6.2no fix listedUBUNTU-CVE-2026-64327
Ubuntu:22.04:LTSlinux-gcp-6.5no fix listedUBUNTU-CVE-2026-64327
Ubuntu:24.04:LTSlinux-gcp-7.07.0.0-1011.11~24.04.1UBUNTU-CVE-2026-64327
Ubuntu:26.04:LTSlinux-gke7.0.0-1006.7UBUNTU-CVE-2026-64327
Ubuntu:22.04:LTSlinux-hwe-5.19no fix listedUBUNTU-CVE-2026-64327
Ubuntu:24.04:LTSlinux-hwe-6.11no fix listedUBUNTU-CVE-2026-64327
Ubuntu:24.04:LTSlinux-hwe-6.14no fix listedUBUNTU-CVE-2026-64327
Ubuntu:24.04:LTSlinux-hwe-6.17no fix listedUBUNTU-CVE-2026-64327
Ubuntu:22.04:LTSlinux-hwe-6.2no fix listedUBUNTU-CVE-2026-64327
Ubuntu:22.04:LTSlinux-hwe-6.5no fix listedUBUNTU-CVE-2026-64327
Ubuntu:24.04:LTSlinux-hwe-7.07.0.0-31.31~24.04.1UBUNTU-CVE-2026-64327
Ubuntu:26.04:LTSlinux-ibm7.0.0-1013.13UBUNTU-CVE-2026-64327
Ubuntu:22.04:LTSlinux-intel-iot-realtimeno fix listedUBUNTU-CVE-2026-64327
Ubuntu:22.04:LTSlinux-lowlatency-hwe-5.19no fix listedUBUNTU-CVE-2026-64327
Ubuntu:24.04:LTSlinux-lowlatency-hwe-6.11no fix listedUBUNTU-CVE-2026-64327
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.2no fix listedUBUNTU-CVE-2026-64327
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.5no fix listedUBUNTU-CVE-2026-64327
Ubuntu:26.04:LTSlinux-nvidia7.0.0-1018.18UBUNTU-CVE-2026-64327
Ubuntu:24.04:LTSlinux-nvidia-6.11no fix listedUBUNTU-CVE-2026-64327
Ubuntu:24.04:LTSlinux-nvidia-6.17no fix listedUBUNTU-CVE-2026-64327
Ubuntu:22.04:LTSlinux-nvidia-6.2no fix listedUBUNTU-CVE-2026-64327
Ubuntu:22.04:LTSlinux-nvidia-6.5no fix listedUBUNTU-CVE-2026-64327
Ubuntu:24.04:LTSlinux-nvidia-7.07.0.0-1018.18~24.04.1UBUNTU-CVE-2026-64327
Ubuntu:26.04:LTSlinux-nvidia-bos7.0.0-2018.18UBUNTU-CVE-2026-64327
Ubuntu:22.04:LTSlinux-oem-5.17no fix listedUBUNTU-CVE-2026-64327
Ubuntu:22.04:LTSlinux-oem-6.0no fix listedUBUNTU-CVE-2026-64327
Ubuntu:22.04:LTSlinux-oem-6.1no fix listedUBUNTU-CVE-2026-64327
Ubuntu:24.04:LTSlinux-oem-6.11no fix listedUBUNTU-CVE-2026-64327
Ubuntu:24.04:LTSlinux-oem-6.14no fix listedUBUNTU-CVE-2026-64327
Ubuntu:24.04:LTSlinux-oem-6.17no fix listedUBUNTU-CVE-2026-64327
Ubuntu:22.04:LTSlinux-oem-6.5no fix listedUBUNTU-CVE-2026-64327
Ubuntu:24.04:LTSlinux-oem-6.8no fix listedUBUNTU-CVE-2026-64327
Ubuntu:26.04:LTSlinux-oem-7.07.0.0-1013.13UBUNTU-CVE-2026-64327
Ubuntu:26.04:LTSlinux-oracle7.0.0-1011.11UBUNTU-CVE-2026-64327
Ubuntu:24.04:LTSlinux-oracle-6.14no fix listedUBUNTU-CVE-2026-64327
Ubuntu:24.04:LTSlinux-oracle-6.17no fix listedUBUNTU-CVE-2026-64327
Ubuntu:22.04:LTSlinux-oracle-6.5no fix listedUBUNTU-CVE-2026-64327
Ubuntu:24.04:LTSlinux-oracle-7.07.0.0-1011.11~24.04.1UBUNTU-CVE-2026-64327
Ubuntu:26.04:LTSlinux-raspi7.0.0-1019.19UBUNTU-CVE-2026-64327
Ubuntu:24.04:LTSlinux-raspi-realtimeno fix listedUBUNTU-CVE-2026-64327
Ubuntu:22.04:LTSlinux-realtimeno fix listedUBUNTU-CVE-2026-64327
Ubuntu:24.04:LTSlinux-realtimeno fix listedUBUNTU-CVE-2026-64327
Ubuntu:26.04:LTSlinux-realtime7.0.0-31.31.1UBUNTU-CVE-2026-64327
Ubuntu:22.04:LTSlinux-riscvno fix listedUBUNTU-CVE-2026-64327
Ubuntu:24.04:LTSlinux-riscvno fix listedUBUNTU-CVE-2026-64327
Ubuntu:26.04:LTSlinux-riscv7.0.0-31.31.1UBUNTU-CVE-2026-64327
Ubuntu:22.04:LTSlinux-riscv-5.19no fix listedUBUNTU-CVE-2026-64327
Ubuntu:24.04:LTSlinux-riscv-6.14no fix listedUBUNTU-CVE-2026-64327
Ubuntu:24.04:LTSlinux-riscv-6.17no fix listedUBUNTU-CVE-2026-64327
Ubuntu:22.04:LTSlinux-riscv-6.5no fix listedUBUNTU-CVE-2026-64327
Ubuntu:24.04:LTSlinux-riscv-7.07.0.0-31.31.1~24.04.1UBUNTU-CVE-2026-64327
Ubuntu:22.04:LTSlinux-starfive-5.19no fix listedUBUNTU-CVE-2026-64327
Ubuntu:22.04:LTSlinux-starfive-6.2no fix listedUBUNTU-CVE-2026-64327
Ubuntu:22.04:LTSlinux-starfive-6.5no fix listedUBUNTU-CVE-2026-64327

Affected products (as reported)

VendorProductVersions
Linux Linux 7b07a2a7ca02a20124b552be96c5a56910795488 – before 82cf1142e5ccf2b6d6d22ef713aaf3e5f2b5716b7b07a2a7ca02a20124b552be96c5a56910795488 – before 9e04055ab5fc0470a0031ee6934739f9aa8f34a57b07a2a7ca02a20124b552be96c5a56910795488 – before f99f32ea9aa976afcbec20647ed33b50a52002c17b07a2a7ca02a20124b552be96c5a56910795488 – before 82cfd4739011bdc7e87b5d585703427e89ddfaa5
Linux Linux 6.9

References