CVE-2026-68119
Received
Received - Intake
TCP-AO Response Padding Uninitialized in Linux Kernel
Vulnerability report for CVE-2026-68119, including description, CVSS score, EPSS score, affected products, exploitability, helpful resources, and attack-flow context.
Publication date: 2026-08-10
Last updated on: 2026-08-10
Assigner: kernel.org
Description
Description
In the Linux kernel, the following vulnerability has been resolved:
tcp: initialize standalone TCP-AO response padding
tcp_v4_send_ack() and tcp_v6_send_response() construct standalone TCP
responses with TCP-AO options. The option length carries the actual MAC
length, but the TCP header length includes the option rounded up to a
four-byte boundary.
tcp_ao_hash_hdr() writes the MAC only. Thus, when the MAC length is not
four-byte aligned, the one to three bytes after the MAC are left
uninitialized and may be transmitted. For the normal TCP-AO hashing
mode, those bytes also have to be initialized before computing the MAC.
Initialize only the alignment padding in the TCP-AO branches, before
hashing the header. Use TCPOPT_NOP, as in the normal TCP-AO output path.
This avoids adding work to non-AO TCP responses while preserving a valid
authenticated header.
CVSS Scores
EPSS Scores
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Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| linux | linux_kernel | * |
Helpful Resources
Exploitability
CWE
KEV
| CWE ID | Description |
|---|---|
| CWE-UNKNOWN |
