---
id: "CVE-2026-98963"
kind: "vulnerability"
aliases: ["CVE-2026-98963"]
title: "Linux kernel btrfs: double unlock and free on failed encoded read"
severity: "unknown"
cvss: null
epss: 0.00206
exploited: false
status: "open"
category: "infrastructure"
products: []
ecosystems: []
tags: ["btrfs", "infrastructure", "kernel", "linux"]
not_affected_if: []
published_at: "2026-10-23T13:17:17+00:00"
first_seen_at: "2026-10-23T21:57:33+00:00"
updated_at: "2026-10-25T12:38:50+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-98963", "first_seen_at": "2026-10-23T21:57:33+00:00"}, {"source": "epss", "url": "https://api.first.org/data/v1/epss?cve=CVE-2026-98963", "first_seen_at": "2026-10-25T12:38:50+00:00"}]
---

# Linux kernel btrfs: double unlock and free on failed encoded read

A btrfs encoded read path in the Linux kernel could return an error after all I/O had already finished, so cleanup ran twice. The sources do not state a confirmed attacker outcome.

_Summary, check and fix written by a model from the sources; labelled as such._

## How to check

- unknown

## Fix

- unknown

## Timeline

- 2026-10-23T21:57:33+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-98963
- 2026-10-25T12:38:50+00:00 epss https://api.first.org/data/v1/epss?cve=CVE-2026-98963

## From the sources

In the Linux kernel, the following vulnerability has been resolved:

btrfs: always return -EIOCBQUEUED after btrfs_uring_read_extent_endio

If all bios finish before btrfs_encoded_read_regular_fill_pages()
returns, it calls btrfs_uring_read_extent_endio() and previously
returned the I/O status.  A negative errno then made
btrfs_uring_read_extent() unlock and free while
btrfs_uring_read_finished() did the same again.

Return -EIOCBQUEUED so only the deferred path cleans up.

---

_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_