CVE-2026-64046 net: tls: prevent chain-after-chain in plain text SG
A flaw in the Linux kernel TLS implementation allows illegal scatterlist chaining, potentially causing a denial of service.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-64046?
CVE-2026-64046 is a critical vulnerability in Linux kernel, published on 19 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official 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.
Weakness: CWE-20
Which versions are affected by CVE-2026-64046?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2026-64046?
Apply the vendor's patch.
Is CVE-2026-64046 being exploited?
There is no known exploitation of CVE-2026-64046 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as BELL-CVE-2026-64046, DEBIAN-CVE-2026-64046, GHSA-3mwm-pxvj-5v4x, UBUNTU-CVE-2026-64046.