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Vulnerability record · CVE-2026-49423 · published 19 August 2026

CVE-2026-49423: Freebsd use of uninitialized resource vulnerability

Freebsd · Freebsd

When building the iovec array for a received TLS 1.2 CBC record, ktls_ocf_tls_cbc_decrypt() incremented the iovec index for every mbuf in the chain, including mbufs that were skipped because they contained only TLS header bytes. This left uninitialized entries in the iovec array. The iovec array was allocated without zeroing. A remote TLS peer can cause the kernel to read from uninitialized iovec entries during HMAC computation, resulting in a kernel panic. The peer must be able to control TCP segmentation such that the first mbuf of a CBC record contains only the 5-byte TLS record header.

3.3 CVSS 3.1 Low EPSS 0.14% · top 97.2% CWE-908 · Use of uninitialized resource
3.3CVSS 3.1 base score
0.14%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
1References
31 Aug 2026Last modified by NVD

Description

When building the iovec array for a received TLS 1.2 CBC record, ktls_ocf_tls_cbc_decrypt() incremented the iovec index for every mbuf in the chain, including mbufs that were skipped because they contained only TLS header bytes. This left uninitialized entries in the iovec array. The iovec array was allocated without zeroing. A remote TLS peer can cause the kernel to read from uninitialized iovec entries during HMAC computation, resulting in a kernel panic. The peer must be able to control TCP segmentation such that the first mbuf of a CBC record contains only the 5-byte TLS record header.

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://security.freebsd.org/advisories/FreeBSD-SA-26:46.ktls.asc Vendor Advisory

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Source: NIST National Vulnerability Database (record CVE-2026-49423), CISA KEV, FIRST EPSS (scores of 2026-10-10). This page is refreshed as NVD updates the record.