CVE-2026-49423

LOWCVSS 3.3/10EPSS 0.10%

Last modified

CVE-2026-49423 is a low-severity vulnerability rated 3.3/10 on the CVSS scale. 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. EPSS estimates a 0.10% chance of exploitation in the next 30 days.

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.

Metrics

EPSS Probability
0.10%

1.1th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

VendorProductVersions
FreebsdFreebsd14.3
FreebsdFreebsd14.4
FreebsdFreebsd15.0
FreebsdFreebsd15.1

References

Timeline

Published
Last Modified
Status
Analyzed

Frequently Asked Questions

What is CVE-2026-49423?
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.
How severe is CVE-2026-49423?
CVE-2026-49423 has a CVSS score of 3.3/10 (LOW severity). The EPSS model estimates a 0.10% probability of exploitation in the next 30 days.
How do I fix CVE-2026-49423?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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Source: NVD / NIST