CVE-2026-64336: Linux kernel · USB: serial: keyspan_pda: fix information leak
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 5.5 Medium · fixed in 5.15.0-1117.124~20.04.1 : update Linux kernel when convenient.
Data as of 26 Oct 2026, 14:05 UTC
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 2% 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 +43
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:HExploitation evidence
Disclosed: evidence found.
CVE published 25 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 vendor-provided patch is available and should be applied to affected Linux kernel versions to resolve the issue. The fix corrects the return value of the write callback to prevent the information leak. Users should update to patched kernel versions as per the Ubuntu security notice USN-8726-1. No additional mitigation steps are indicated by the vendor advisory.
Description
A vulnerability in the Linux kernel's USB serial driver for keyspan_pda devices could cause an information leak due to improper handling of the write() callback. The flaw causes the driver to return a count of characters larger than those actually passed, leading to potential data leakage beyond the intended buffer. This issue has been fixed by correcting the return value behavior in the keyspan_pda_write_start() function. The vulnerability has a medium severity score and affects multiple Linux kernel versions. A patch is available from the vendor.
References
- nvd.nist.gov/vuln/detail/CVE-2026-64336 (opens in a new tab)
- git.kernel.org/stable/c/2f7a6b8ab3845bd1da02604f1a874b52a4555a72 (opens in a new tab)
- git.kernel.org/stable/c/6bfc8d01ac4068eced509f8fc74d0cd205e4dcec (opens in a new tab)
- git.kernel.org/stable/c/b069b7029862fafaff331d4c664d97d4ae828d6d (opens in a new tab)
- git.kernel.org/stable/c/cf6ca0aefae03958cfb5b189b0adbfb25c06bfac (opens in a new tab)
- git.kernel.org/stable/c/d4b12b6b395e43a2b1d80be3745631fcaa9c047b (opens in a new tab)
- git.kernel.org/stable/c/e1494191a3aac665d3a2fce16169a97c346253ec (opens in a new tab)
- git.kernel.org/stable/c/e52ca411f50539ff1d0c877b9312771ca8a858c1 (opens in a new tab)
- ubuntu.com/security/CVE-2026-64336 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-64336 (opens in a new tab)
- git.kernel.org/linus/6bfc8d01ac4068eced509f8fc74d0cd205e4dcec (opens in a new tab)
- ubuntu.com/security/notices/USN-8726-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8727-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8728-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8760-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8726-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8726-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-8800-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8760-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8728-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8726-4 (opens in a new tab)