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.
Metrics
Affected Vendors & Products
No advisories yet.
Solution
No solution given by the vendor.
Workaround
No workaround given by the vendor.
Thu, 13 Aug 2026 22:45:00 +0000
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cvssV3_1
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cvssV3_1
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Thu, 13 Aug 2026 09:30:00 +0000
| Type | Values Removed | Values Added |
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| Weaknesses | CWE-457 |
Wed, 12 Aug 2026 00:15:00 +0000
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| Weaknesses | CWE-908 | |
| References |
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| Metrics |
threat_severity
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cvssV3_1
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Mon, 10 Aug 2026 14:00:00 +0000
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| Weaknesses | CWE-457 |
Mon, 10 Aug 2026 12:30:00 +0000
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| 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. | |
| Title | tcp: initialize standalone TCP-AO response padding | |
| First Time appeared |
Linux
Linux linux Kernel |
|
| CPEs | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Linux
Linux linux Kernel |
|
| References |
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Projects
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Status: PUBLISHED
Assigner: Linux
Published:
Updated: 2026-08-13T22:39:55.693Z
Reserved: 2026-07-30T09:28:09.369Z
Link: CVE-2026-68119
No data.
Status : Received
Published: 2026-08-10T13:19:56.960
Modified: 2026-08-13T23:17:17.137
Link: CVE-2026-68119
OpenCVE Enrichment
Updated: 2026-08-14T00:15:04Z