Local information disclosure via inflated write return
Published Jul 25, 2026 · Updated Jul 25, 2026
Out-of-bounds read in the Linux Kernel keyspan_pda USB serial driver allows local users to disclose kernel data through device writes. When no write URB is active, keyspan_pda_write_start() returns the amount submitted to the device instead of zero, causing write() to overstate the accepted length and the line discipline to read past the tty write buffer. Exploitation requires local low-privileged access and a Keyspan-compatible USB serial device; excess buffer contents are transmitted to that device.
Summary
What happened
Out-of-bounds read in the Linux Kernel keyspan_pda USB serial driver allows local users to disclose kernel data through device writes. When no write URB is active, keyspan_pda_write_start() returns the amount submitted to the device instead of zero, causing write() to overstate the accepted length and the line discipline to read past the tty write buffer. Exploitation requires local low-privileged access and a Keyspan-compatible USB serial device; excess buffer contents are transmitted to that device.
The record
- CVE
- CVE-2026-64336
- Published
- Jul 25, 2026
- Updated
- Jul 25, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux Kernel
- Classifications
- CWE-787, T1005
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Jul 25, 2026CVE publishedPublication date reported by the CVE source.
- Jul 25, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
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- Affected versionversion=034e38e8f68767fb5438ae3e608ee82919674177 <2f7a6b8ab3845bd1da02604f1a874b52a4555a72
- Affected versionversion=034e38e8f68767fb5438ae3e608ee82919674177 <6bfc8d01ac4068eced509f8fc74d0cd205e4dcec
- Affected versionversion=034e38e8f68767fb5438ae3e608ee82919674177 <b069b7029862fafaff331d4c664d97d4ae828d6d
- Affected versionversion=034e38e8f68767fb5438ae3e608ee82919674177 <cf6ca0aefae03958cfb5b189b0adbfb25c06bfac
- Affected versionversion=034e38e8f68767fb5438ae3e608ee82919674177 <d4b12b6b395e43a2b1d80be3745631fcaa9c047b
- Affected versionversion=034e38e8f68767fb5438ae3e608ee82919674177 <e1494191a3aac665d3a2fce16169a97c346253ec
- Affected versionversion=034e38e8f68767fb5438ae3e608ee82919674177 <e52ca411f50539ff1d0c877b9312771ca8a858c1
- Affected versionversion=5.11
What conditions does exploitation require?
What is affected?
Published CVSS scores
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Attacks
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Technologies
Your stack
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Your stack
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