CVE-2026-64046
Received Received - Intake

Heap Overflow in Linux Kernel TLS Implementation

Vulnerability report for CVE-2026-64046, including description, CVSS score, EPSS score, affected products, exploitability, helpful resources, and attack-flow context.

Publication date: 2026-07-19

Last updated on: 2026-07-19

Assigner: kernel.org

Description

In the Linux kernel, the following vulnerability has been resolved: net: tls: prevent chain-after-chain in plain text SG Sashiko points out that if end = 0 (start != 0) the current code will create a chain link to content type right after the wrap link: This would create a chain where the wrap link points directly to another chain link. The scatterlist API sg_next iterator does not recursively resolve consecutive chain links. meaning this is illegal input to crypto. The wrapping link is unnecessary if end = 0. end is the entry after the last one used so end = 0 means there's nothing pushed after the wrap: end start i v v v [ ]...[ ][ d ][ d ][ d ][ d ][rsv for wrap] Skip the wrapping in this case. TLS 1.3 can use the "wrapping slot" for it's chaining if end = 0. This avoids the chain-after-chain. Move the wrap chaining before marking END and chaining off content type, that feels like more logical ordering to me, but should not matter from functional perspective.

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Meta Information

Published
2026-07-19
Last Modified
2026-07-19
Generated
2026-07-20
AI Q&A
2026-07-19
EPSS Evaluated
N/A
NVD
EUVD

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
linux linux_kernel *

Helpful Resources

Exploitability

CWE
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CWE ID Description
CWE-UNKNOWN

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Executive Summary

This vulnerability in the Linux kernel involves improper handling of scatter-gather (SG) lists in the TLS implementation. When end=0 but start!=0, the code incorrectly creates a chain link to content type after a wrap link, violating the scatterlist API's requirement that chain links must not point to other chain links. This results in illegal input to the crypto system.

Detection Guidance

This vulnerability is specific to the Linux kernel's TLS implementation and requires kernel-level inspection. Detection involves checking kernel logs for TLS-related errors or examining kernel memory for illegal scatterlist chains. Commands like dmesg | grep tls or checking kernel logs for TLS-related warnings may help. No direct network commands are applicable.

Impact Analysis

This vulnerability could lead to cryptographic operations failing or producing incorrect results due to invalid SG list chaining. It may cause TLS connections to malfunction, potentially disrupting secure communications or leading to system instability in affected Linux kernel versions.

Compliance Impact

The provided CVE data does not describe any direct impact on compliance with GDPR, HIPAA, or similar standards. The vulnerability is a low-level kernel issue affecting TLS 1.3 chaining in the Linux kernel, which may lead to illegal scatterlist API usage but does not explicitly mention data protection or privacy implications.

Mitigation Strategies

Update the Linux kernel to the latest patched version to resolve this vulnerability. Monitor vendor advisories for kernel updates and apply them promptly.

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