CVE-2026-63895: Linux kernel · usb: gadget: f_fs: copy only received bytes on short ep0 read
Affects Linux kernelSource GCVE Database
Not known to be exploited · fixed in 5.15.0-1117.124~20.04.1 : update Linux kernel when convenient.
Data as of 26 Oct 2026, 14:05 UTC
Rated by Threat Radar · No CVSS score from NVD or the CNA
- EPSS
- 0.2% chance of exploitation in 30 days – higher than 17% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 5.15.0-1117.124~20.04.1, 5.15.0-1123.132~20.04.1, 5.15.0-1122.131~20.04.1 +65
Exploitation evidence
Disclosed: evidence found.
CVE published 20 Jul 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
Upgrade to a fixed release listed under Affected software.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 26.04 LTSlinuxpkg:deb/ubuntu/linux?arch=source&distro=resoluteOther threats | Affected
| Fixed in
|
Ubuntu 26.04 LTSlinux-awspkg:deb/ubuntu/linux-aws?arch=source&distro=resoluteOther threats | Affected
| Fixed in
|
Ubuntu 26.04 LTSlinux-azurepkg:deb/ubuntu/linux-azure?arch=source&distro=resoluteOther threats | Affected
| Fixed in
|
Ubuntu 26.04 LTSlinux-azure-fdepkg:deb/ubuntu/linux-azure-fde?arch=source&distro=resoluteOther threats | Affected
| Fixed in
|
Ubuntu 26.04 LTSlinux-gcppkg:deb/ubuntu/linux-gcp?arch=source&distro=resoluteOther threats | Affected
| Fixed in
|
Ubuntu 26.04 LTSlinux-gkepkg:deb/ubuntu/linux-gke?arch=source&distro=resoluteOther threats | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
A fix is available and has been applied in updated Linux kernel versions. Users and administrators should apply the official kernel updates that address this vulnerability to prevent potential memory leakage.
Description
A vulnerability in the Linux kernel's USB gadget function (ffs_ep0_read) caused more bytes to be copied to userspace than were actually received during short control OUT transfers on endpoint 0. This could lead to leakage of uninitialized kernel memory. The issue deviated from USB control-transfer specifications and affected in-tree USB device controllers. The vulnerability has been fixed in updated Linux kernel versions.
References
- nvd.nist.gov/vuln/detail/CVE-2026-63895 (opens in a new tab)
- git.kernel.org/stable/c/23c1f7deb9dd8447ecde749850676302aa1e2bd3 (opens in a new tab)
- git.kernel.org/stable/c/4e036c10e7f4df5d951c69cc3697bc8e209c6d02 (opens in a new tab)
- git.kernel.org/stable/c/607730a414773a7cbe3037a64a6c64e72689ff5e (opens in a new tab)
- git.kernel.org/stable/c/88874a19b2b093bfaaa1c0090fa536c44da8c08b (opens in a new tab)
- git.kernel.org/stable/c/90ccf5fb63243fae1b4b3200f3310500500ecf2e (opens in a new tab)
- git.kernel.org/stable/c/af32dbb2ca0b3d09271ab718d13857a457fa16f2 (opens in a new tab)
- git.kernel.org/stable/c/e835bf9a055f71874065a40780ca5560b7df8b33 (opens in a new tab)
- ubuntu.com/security/CVE-2026-63895 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-63895 (opens in a new tab)
- git.kernel.org/linus/4e036c10e7f4df5d951c69cc3697bc8e209c6d02 (opens in a new tab)
- ubuntu.com/security/notices/USN-8593-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8603-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8618-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8663-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8664-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8728-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8728-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8728-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-8878-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8879-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8877-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8875-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8903-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8905-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8906-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8904-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8903-2 (opens in a new tab)