CVE Catalog

CVE-2026-68119

HighCVSS 7.5
Published: Updated: Translated: NVD NIST

Exploitation Probability (EPSS)

Low risk
0.37%

30th percentile - higher than 30% of all known CVEs

Summary

In the Linux kernel, in tcp_v4_send_ack() and tcp_v6_send_response(), when constructing standalone TCP responses with TCP-AO options, the alignment padding bytes after the MAC are left uninitialized and may be transmitted. The fix initializes only the padding in the TCP-AO branches before hashing the header.

Risk Assessment

Uninitialized kernel data may leak to the network, potentially exposing sensitive information. Additionally, in TCP-AO hashing mode, it may affect authentication integrity.

Recommendation

Apply the official Linux kernel patch that initializes padding bytes in TCP-AO responses to prevent data leakage and ensure authentication correctness.

Other vulnerabilities in Linux kernel

See all
Original NVD description (English source)

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.

Vulnerability data from NVD (NIST) · CISA KEV · EPSS