CVE-2026-63957: Linux kernel · USB: serial: safe_serial: fix memory corruption with small endpoint
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 11% 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 through official Ubuntu kernel updates. Users should apply these updates promptly. Note that applying the update requires a system reboot and recompilation of any third-party kernel modules due to an ABI change. Follow the vendor advisory for detailed update instructions.
Description
A memory corruption vulnerability in the Linux kernel's USB serial safe_serial driver was fixed by ensuring the bulk-out buffer size is at least eight bytes. This prevents user-controlled slab corruption caused by malicious USB devices reporting smaller sizes. The vulnerability affects multiple Linux kernel versions prior to specific patched releases. Official Ubuntu kernel updates address this issue, requiring a system reboot and recompilation of third-party kernel modules due to an ABI change.
References
- nvd.nist.gov/vuln/detail/CVE-2026-63957 (opens in a new tab)
- git.kernel.org/stable/c/161ea0e5236f5f051d2d85d6c54dd08ee9dc7ba4 (opens in a new tab)
- git.kernel.org/stable/c/438061ed1ad85e6743e2dce826671772d81089ec (opens in a new tab)
- git.kernel.org/stable/c/857b3cc73f91871ae4433f8b97c4670b78f8dc96 (opens in a new tab)
- git.kernel.org/stable/c/9b3145b3001fb24de1da72d1deb0bea70e5a078b (opens in a new tab)
- git.kernel.org/stable/c/a550ed2117ca4709d38f713933ff924a83942e41 (opens in a new tab)
- git.kernel.org/stable/c/c7336c0fba5c959249f3d793d33076b992ec3ee4 (opens in a new tab)
- git.kernel.org/stable/c/e3a1d6eee25dc96b1d2db0ecd9d8741e92056476 (opens in a new tab)
- git.kernel.org/stable/c/f793b67d41e5fab719c5a90baa77cbd2fe259517 (opens in a new tab)
- ubuntu.com/security/CVE-2026-63957 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-63957 (opens in a new tab)
- git.kernel.org/linus/438061ed1ad85e6743e2dce826671772d81089ec (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)