# CVE-2026-63896: linux: In the Linux kernel, the following vulnerability has been resolved: usb: gadget: composite: fix integer underflow in... CVE-2026-63896 is fixed in 53 products on 1 platform, first by ALAS2023-2026-1881, released June 22, 2026. It is not reported as exploited. Patch Radar priority: High. - Web page: https://patchblox.com/security/cve/CVE-2026-63896 - Priority: High - CVSS: n/a (important) - EPSS: 0.0021 - CISA KEV: not listed - Exploited (vendor report): no - Publicly disclosed: no - Published: Jun 22, 2026 ## Description In the Linux kernel, the following vulnerability has been resolved: usb: gadget: composite: fix integer underflow in WebUSB GET_URL handling The WebUSB GET_URL handler in composite_setup() narrows landing_page_length to fit the host-supplied wLength using landing_page_length = w_length - WEBUSB_URL_DESCRIPTOR_HEADER_LENGTH + landing_page_offset; If wLength is smaller than WEBUSB_URL_DESCRIPTOR_HEADER_LENGTH the unsigned subtraction wraps, and the subsequent memcpy(url_descriptor->URL, cdev->landing_page + landing_page_offset, landing_page_length - landing_page_offset); ends up copying close to UINT_MAX bytes from cdev->landing_page into cdev->req->buf. KASAN reports a slab-out-of-bounds in composite_setup on the kmalloc-2k gadget_info allocation, and FORTIFY_SOURCE traps the memcpy as a 4294967293-byte field-spanning write into url_descriptor->URL (size 252). A USB host can reach this from a single SETUP packet against any gadget that has webusb/use=1 and a landingPage configured. Handle the small-wLength case before the math: when the host requested fewer bytes than the URL descriptor header, only the header is meaningful and no URL bytes need to be copied. Setting landing_page_length to landing_page_offset makes the existing memcpy a no-op and leaves the descriptor returned to the host unchanged for all larger wLength values. ## Where it's fixed | Platform | Product | Fixed in | Fix | Released | |---|---|---|---|---| | Linux | bpftool6.12 amzn 2023 | 1:6.12.94-123.174.amzn2023 | [ALAS2023-2026-1968](https://patchblox.com/security/data/fix/linux/alas2023-2026-1968.md) | Jul 20, 2026 | | Linux | bpftool6.12-debuginfo amzn 2023 | 1:6.12.94-123.174.amzn2023 | [ALAS2023-2026-1968](https://patchblox.com/security/data/fix/linux/alas2023-2026-1968.md) | Jul 20, 2026 | | Linux | bpftool6.18 amzn 2023 | 1:6.18.35-68.127.amzn2023 | [ALAS2023-2026-1881](https://patchblox.com/security/data/fix/linux/alas2023-2026-1881.md) | Jun 22, 2026 | | Linux | bpftool6.18-debuginfo amzn 2023 | 1:6.18.35-68.127.amzn2023 | [ALAS2023-2026-1881](https://patchblox.com/security/data/fix/linux/alas2023-2026-1881.md) | Jun 22, 2026 | | Linux | dtb-aarch64 opensuse-leap 16.0 | 6.12.0-160000.37.1 | [OPENSUSE-SU-2026:21555-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21555-1.md) | Aug 12, 2026 | | Linux | kernel-64kb opensuse-leap 16.0 | 6.12.0-160000.37.1 | [OPENSUSE-SU-2026:21555-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21555-1.md) | Aug 12, 2026 | | Linux | kernel-64kb sles 15.7 | 6.4.0-150700.53.78.1 | [SUSE-SU-2026:3790-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-3790-1.md) | Aug 25, 2026 | | Linux | kernel-64kb sles 16.0 | 6.12.0-160000.37.1 | [SUSE-SU-2026:23231-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-23231-1.md) | Aug 11, 2026 | | Linux | kernel-azure opensuse-leap 16.0 | 6.12.0-160000.37.1 | [OPENSUSE-SU-2026:21555-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21555-1.md) | Aug 12, 2026 | | Linux | kernel-azure sles 15.7 | 6.4.0-150700.53.78.1 | [SUSE-SU-2026:3790-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-3790-1.md) | Aug 25, 2026 | | Linux | kernel-azure sles 16.0 | 6.12.0-160000.37.1 | [SUSE-SU-2026:23231-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-23231-1.md) | Aug 11, 2026 | | Linux | kernel-default opensuse-leap 16.0 | 6.12.0-160000.37.1 | [OPENSUSE-SU-2026:21555-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21555-1.md) | Aug 12, 2026 | | Linux | kernel-default sles 15.7 | 6.4.0-150700.53.78.1 | [SUSE-SU-2026:3790-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-3790-1.md) | Aug 25, 2026 | | Linux | kernel-default sles 16.0 | 6.12.0-160000.37.1 | [SUSE-SU-2026:23237-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-23237-1.md) | Aug 11, 2026 | | Linux | kernel-default-base opensuse-leap 16.0 | 6.12.0-160000.37.1.160000.2.19 | [OPENSUSE-SU-2026:21555-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21555-1.md) | Aug 12, 2026 | | Linux | kernel-default-base sles 15.7 | 6.4.0-150700.53.78.1.150700.17.43.2 | [SUSE-SU-2026:3790-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-3790-1.md) | Aug 25, 2026 | | Linux | kernel-default-base sles 16.0 | 6.12.0-160000.37.1.160000.2.19 | [SUSE-SU-2026:23231-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-23231-1.md) | Aug 11, 2026 | | Linux | kernel-docs opensuse-leap 16.0 | 6.12.0-160000.37.1 | [OPENSUSE-SU-2026:21555-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21555-1.md) | Aug 12, 2026 | | Linux | kernel-docs sles 15.7 | 6.4.0-150700.53.78.1 | [SUSE-SU-2026:3790-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-3790-1.md) | Aug 25, 2026 | | Linux | kernel-docs sles 16.0 | 6.12.0-160000.37.1 | [SUSE-SU-2026:23231-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-23231-1.md) | Aug 11, 2026 | | Linux | kernel-kvmsmall opensuse-leap 16.0 | 6.12.0-160000.37.1 | [OPENSUSE-SU-2026:21555-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21555-1.md) | Aug 12, 2026 | | Linux | kernel-kvmsmall sles 16.0 | 6.12.0-160000.37.1 | [SUSE-SU-2026:23231-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-23231-1.md) | Aug 11, 2026 | | Linux | kernel-livepatch-6.12.94-123.174 amzn 2023 | 1:1.0-0.amzn2023 | [ALAS2023-2026-1968](https://patchblox.com/security/data/fix/linux/alas2023-2026-1968.md) | Jul 20, 2026 | | Linux | kernel-livepatch-6.18.35-68.127 amzn 2023 | 1:1.0-0.amzn2023 | [ALAS2023-2026-1881](https://patchblox.com/security/data/fix/linux/alas2023-2026-1881.md) | Jun 22, 2026 | | Linux | kernel-livepatch-SLE15-SP7-RT_Update_19 sles 15.7 | 1-150700.1.5.1 | [SUSE-SU-2026:3810-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-3810-1.md) | Aug 26, 2026 | | Linux | kernel-livepatch-SLE15-SP7_Update_20 sles 15.7 | 1-150700.15.3.2 | [SUSE-SU-2026:3790-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-3790-1.md) | Aug 25, 2026 | | Linux | kernel-obs-build opensuse-leap 16.0 | 6.12.0-160000.37.1 | [OPENSUSE-SU-2026:21555-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21555-1.md) | Aug 12, 2026 | | Linux | kernel-obs-build sles 15.7 | 6.4.0-150700.53.78.1 | [SUSE-SU-2026:3790-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-3790-1.md) | Aug 25, 2026 | | Linux | kernel-obs-qa opensuse-leap 16.0 | 6.12.0-160000.37.1 | [OPENSUSE-SU-2026:21555-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21555-1.md) | Aug 12, 2026 | | Linux | kernel-obs-qa sles 16.0 | 6.12.0-160000.37.1 | [SUSE-SU-2026:23231-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-23231-1.md) | Aug 11, 2026 | | Linux | kernel-rt opensuse-leap 16.0 | 6.12.0-160000.37.1 | [OPENSUSE-SU-2026:21555-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21555-1.md) | Aug 12, 2026 | | Linux | kernel-source opensuse-leap 16.0 | 6.12.0-160000.37.1 | [OPENSUSE-SU-2026:21555-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21555-1.md) | Aug 12, 2026 | | Linux | kernel-source sles 15.7 | 6.4.0-150700.53.78.1 | [SUSE-SU-2026:3790-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-3790-1.md) | Aug 25, 2026 | | Linux | kernel-source sles 16.0 | 6.12.0-160000.37.1 | [SUSE-SU-2026:23231-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-23231-1.md) | Aug 11, 2026 | | Linux | kernel-syms opensuse-leap 16.0 | 6.12.0-160000.37.1 | [OPENSUSE-SU-2026:21555-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21555-1.md) | Aug 12, 2026 | | Linux | kernel-syms sles 15.7 | 6.4.0-150700.53.78.1 | [SUSE-SU-2026:3790-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-3790-1.md) | Aug 25, 2026 | | Linux | kernel-syms sles 16.0 | 6.12.0-160000.37.1 | [SUSE-SU-2026:23231-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-23231-1.md) | Aug 11, 2026 | | Linux | kernel-zfcpdump opensuse-leap 16.0 | 6.12.0-160000.37.1 | [OPENSUSE-SU-2026:21555-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21555-1.md) | Aug 12, 2026 | | Linux | kernel-zfcpdump sles 15.7 | 6.4.0-150700.53.78.1 | [SUSE-SU-2026:3790-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-3790-1.md) | Aug 25, 2026 | | Linux | kernel-zfcpdump sles 16.0 | 6.12.0-160000.37.1 | [SUSE-SU-2026:23231-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-23231-1.md) | Aug 11, 2026 | | Linux | kernel6.12 amzn 2023 | 1:6.12.94-123.174.amzn2023 | [ALAS2023-2026-1968](https://patchblox.com/security/data/fix/linux/alas2023-2026-1968.md) | Jul 20, 2026 | | Linux | kernel6.12-debuginfo amzn 2023 | 1:6.12.94-123.174.amzn2023 | [ALAS2023-2026-1968](https://patchblox.com/security/data/fix/linux/alas2023-2026-1968.md) | Jul 20, 2026 | | Linux | kernel6.12-debuginfo-common-aarch64 amzn 2023 | 1:6.12.94-123.174.amzn2023 | [ALAS2023-2026-1968](https://patchblox.com/security/data/fix/linux/alas2023-2026-1968.md) | Jul 20, 2026 | | Linux | kernel6.12-debuginfo-common-x86_64 amzn 2023 | 1:6.12.94-123.174.amzn2023 | [ALAS2023-2026-1968](https://patchblox.com/security/data/fix/linux/alas2023-2026-1968.md) | Jul 20, 2026 | | Linux | kernel6.12-devel amzn 2023 | 1:6.12.94-123.174.amzn2023 | [ALAS2023-2026-1968](https://patchblox.com/security/data/fix/linux/alas2023-2026-1968.md) | Jul 20, 2026 | | Linux | kernel6.12-headers amzn 2023 | 1:6.12.94-123.174.amzn2023 | [ALAS2023-2026-1968](https://patchblox.com/security/data/fix/linux/alas2023-2026-1968.md) | Jul 20, 2026 | | Linux | kernel6.12-modules-extra amzn 2023 | 1:6.12.94-123.174.amzn2023 | [ALAS2023-2026-1968](https://patchblox.com/security/data/fix/linux/alas2023-2026-1968.md) | Jul 20, 2026 | | Linux | kernel6.12-modules-extra-common amzn 2023 | 1:6.12.94-123.174.amzn2023 | [ALAS2023-2026-1968](https://patchblox.com/security/data/fix/linux/alas2023-2026-1968.md) | Jul 20, 2026 | | Linux | kernel6.12-tools amzn 2023 | 1:6.12.94-123.174.amzn2023 | [ALAS2023-2026-1968](https://patchblox.com/security/data/fix/linux/alas2023-2026-1968.md) | Jul 20, 2026 | | Linux | kernel6.12-tools-debuginfo amzn 2023 | 1:6.12.94-123.174.amzn2023 | [ALAS2023-2026-1968](https://patchblox.com/security/data/fix/linux/alas2023-2026-1968.md) | Jul 20, 2026 | | Linux | kernel6.12-tools-devel amzn 2023 | 1:6.12.94-123.174.amzn2023 | [ALAS2023-2026-1968](https://patchblox.com/security/data/fix/linux/alas2023-2026-1968.md) | Jul 20, 2026 | | Linux | kernel6.18 amzn 2023 | 1:6.18.35-68.127.amzn2023 | [ALAS2023-2026-1881](https://patchblox.com/security/data/fix/linux/alas2023-2026-1881.md) | Jun 22, 2026 | | Linux | kernel6.18-debuginfo amzn 2023 | 1:6.18.35-68.127.amzn2023 | [ALAS2023-2026-1881](https://patchblox.com/security/data/fix/linux/alas2023-2026-1881.md) | Jun 22, 2026 | | Linux | kernel6.18-debuginfo-common-aarch64 amzn 2023 | 1:6.18.35-68.127.amzn2023 | [ALAS2023-2026-1881](https://patchblox.com/security/data/fix/linux/alas2023-2026-1881.md) | Jun 22, 2026 | | Linux | kernel6.18-debuginfo-common-x86_64 amzn 2023 | 1:6.18.35-68.127.amzn2023 | [ALAS2023-2026-1881](https://patchblox.com/security/data/fix/linux/alas2023-2026-1881.md) | Jun 22, 2026 | | Linux | kernel6.18-devel amzn 2023 | 1:6.18.35-68.127.amzn2023 | [ALAS2023-2026-1881](https://patchblox.com/security/data/fix/linux/alas2023-2026-1881.md) | Jun 22, 2026 | | Linux | kernel6.18-headers amzn 2023 | 1:6.18.35-68.127.amzn2023 | [ALAS2023-2026-1881](https://patchblox.com/security/data/fix/linux/alas2023-2026-1881.md) | Jun 22, 2026 | | Linux | kernel6.18-modules-extra amzn 2023 | 1:6.18.35-68.127.amzn2023 | [ALAS2023-2026-1881](https://patchblox.com/security/data/fix/linux/alas2023-2026-1881.md) | Jun 22, 2026 | | Linux | kernel6.18-modules-extra-common amzn 2023 | 1:6.18.35-68.127.amzn2023 | [ALAS2023-2026-1881](https://patchblox.com/security/data/fix/linux/alas2023-2026-1881.md) | Jun 22, 2026 | | Linux | kernel6.18-tools amzn 2023 | 1:6.18.35-68.127.amzn2023 | [ALAS2023-2026-1881](https://patchblox.com/security/data/fix/linux/alas2023-2026-1881.md) | Jun 22, 2026 | | Linux | kernel6.18-tools-debuginfo amzn 2023 | 1:6.18.35-68.127.amzn2023 | [ALAS2023-2026-1881](https://patchblox.com/security/data/fix/linux/alas2023-2026-1881.md) | Jun 22, 2026 | | Linux | kernel6.18-tools-devel amzn 2023 | 1:6.18.35-68.127.amzn2023 | [ALAS2023-2026-1881](https://patchblox.com/security/data/fix/linux/alas2023-2026-1881.md) | Jun 22, 2026 | | Linux | linux Debian 13.5 (trixie) | 6.12.94-1 | [DEBIAN-CVE-2026-63896](https://patchblox.com/security/data/fix/linux/debian-cve-2026-63896.md) | Jul 20, 2026 | | Linux | linux Debian 14 | 7.0.12-1 | [DEBIAN-CVE-2026-63896](https://patchblox.com/security/data/fix/linux/debian-cve-2026-63896.md) | Jul 20, 2026 | | Linux | microvm-kernel6.18 amzn 2023 | 1:6.18.35-68.127.amzn2023 | [ALAS2023-2026-1881](https://patchblox.com/security/data/fix/linux/alas2023-2026-1881.md) | Jun 22, 2026 | | Linux | perf6.12 amzn 2023 | 1:6.12.94-123.174.amzn2023 | [ALAS2023-2026-1968](https://patchblox.com/security/data/fix/linux/alas2023-2026-1968.md) | Jul 20, 2026 | | Linux | perf6.12-debuginfo amzn 2023 | 1:6.12.94-123.174.amzn2023 | [ALAS2023-2026-1968](https://patchblox.com/security/data/fix/linux/alas2023-2026-1968.md) | Jul 20, 2026 | | Linux | perf6.18 amzn 2023 | 1:6.18.35-68.127.amzn2023 | [ALAS2023-2026-1881](https://patchblox.com/security/data/fix/linux/alas2023-2026-1881.md) | Jun 22, 2026 | | Linux | perf6.18-debuginfo amzn 2023 | 1:6.18.35-68.127.amzn2023 | [ALAS2023-2026-1881](https://patchblox.com/security/data/fix/linux/alas2023-2026-1881.md) | Jun 22, 2026 | | Linux | python3-perf6.12 amzn 2023 | 1:6.12.94-123.174.amzn2023 | [ALAS2023-2026-1968](https://patchblox.com/security/data/fix/linux/alas2023-2026-1968.md) | Jul 20, 2026 | | Linux | python3-perf6.12-debuginfo amzn 2023 | 1:6.12.94-123.174.amzn2023 | [ALAS2023-2026-1968](https://patchblox.com/security/data/fix/linux/alas2023-2026-1968.md) | Jul 20, 2026 | | Linux | python3-perf6.18 amzn 2023 | 1:6.18.35-68.127.amzn2023 | [ALAS2023-2026-1881](https://patchblox.com/security/data/fix/linux/alas2023-2026-1881.md) | Jun 22, 2026 | | Linux | python3-perf6.18-debuginfo amzn 2023 | 1:6.18.35-68.127.amzn2023 | [ALAS2023-2026-1881](https://patchblox.com/security/data/fix/linux/alas2023-2026-1881.md) | Jun 22, 2026 | --- Data as of 2026-11-10T01:44:33Z UTC. 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