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9.8

CVE-2026-89654: Ceph on Linux kernel may crash from session race

CVE-2026-89654 · published 1 month ago
Summary

The Ceph storage client built into the Linux kernel could accidentally use memory that has already been released, leading to a crash or instability. This happens when multiple processes update the cluster map at the same time. Install the latest kernel updates from your Linux distribution to get the fix.

What to do
  • Update debian linux to version 7.2.6-1.
  • Update linux kernel to version 7.2.4.
  • Update linux linux to version 21d5be092d947f8d83f76f7ebf3989e7e9230a98 or later.
Affected software
Ecosystem VendorProductAffected versions
Debian:12 debian linux All versions
– linux linux 2.6.34
< 21d5be092d947f8d83f76f7ebf3989e7e9230a98
Debian:14 debian linux < 7.2.6-1
Fix: upgrade to 7.2.6-1
Linux linux kernel < 7.2.4
>= 2.6.34, < 7.2.4
Fix: upgrade to 7.2.4
Ubuntu:Pro:14.04:LTS canonical linux All versions
Ubuntu:Pro:14.04:LTS canonical linux-aws All versions
Ubuntu:Pro:14.04:LTS canonical linux-azure All versions
Ubuntu:Pro:14.04:LTS canonical linux-lts-xenial All versions
Ubuntu:Pro:16.04:LTS canonical linux-aws-hwe All versions
Ubuntu:Pro:16.04:LTS canonical linux-gcp All versions
Ubuntu:Pro:16.04:LTS canonical linux-hwe All versions
Ubuntu:16.04:LTS canonical linux-hwe-edge All versions
Ubuntu:Pro:16.04:LTS canonical linux-kvm All versions
Ubuntu:Pro:16.04:LTS canonical linux-oracle All versions
Ubuntu:Pro:FIPS:16.04:LTS canonical linux-fips All versions
Ubuntu:18.04:LTS canonical linux-aws-5.0 All versions
Ubuntu:18.04:LTS canonical linux-aws-5.3 All versions
Ubuntu:Pro:18.04:LTS canonical linux-aws-5.4 All versions
Ubuntu:Pro:18.04:LTS canonical linux-azure-4.15 All versions
Ubuntu:18.04:LTS canonical linux-azure-5.3 All versions
Ubuntu:Pro:18.04:LTS canonical linux-azure-5.4 All versions
Ubuntu:18.04:LTS canonical linux-azure-edge All versions
Ubuntu:Pro:18.04:LTS canonical linux-gcp-4.15 All versions
Ubuntu:18.04:LTS canonical linux-gcp-5.3 All versions
Ubuntu:Pro:18.04:LTS canonical linux-gcp-5.4 All versions
Ubuntu:18.04:LTS canonical linux-gke-4.15 All versions
Ubuntu:18.04:LTS canonical linux-gke-5.4 All versions
Ubuntu:18.04:LTS canonical linux-gkeop-5.4 All versions
Ubuntu:Pro:18.04:LTS canonical linux-hwe-5.4 All versions
Ubuntu:Pro:18.04:LTS canonical linux-ibm-5.4 All versions
Ubuntu:18.04:LTS canonical linux-oem All versions
Ubuntu:18.04:LTS canonical linux-oracle-5.0 All versions
Ubuntu:18.04:LTS canonical linux-oracle-5.3 All versions
Ubuntu:Pro:18.04:LTS canonical linux-oracle-5.4 All versions
Ubuntu:Pro:18.04:LTS canonical linux-raspi-5.4 All versions
Ubuntu:Pro:FIPS-updates:18.04:LTS canonical linux-aws-fips All versions
Ubuntu:Pro:FIPS-updates:18.04:LTS canonical linux-azure-fips All versions
Ubuntu:Pro:FIPS-updates:18.04:LTS canonical linux-gcp-fips All versions
Ubuntu:20.04:LTS canonical linux-aws-5.11 All versions
Ubuntu:20.04:LTS canonical linux-aws-5.13 All versions
Ubuntu:Pro:20.04:LTS canonical linux-aws-5.15 All versions
Ubuntu:20.04:LTS canonical linux-aws-5.8 All versions
Ubuntu:20.04:LTS canonical linux-azure-5.11 All versions
Ubuntu:20.04:LTS canonical linux-azure-5.13 All versions
Ubuntu:Pro:20.04:LTS canonical linux-azure-5.15 All versions
Ubuntu:20.04:LTS canonical linux-azure-5.8 All versions
Ubuntu:20.04:LTS canonical linux-azure-fde All versions
Ubuntu:Pro:20.04:LTS canonical linux-azure-fde-5.15 All versions
Ubuntu:Pro:20.04:LTS canonical linux-bluefield All versions
Ubuntu:20.04:LTS canonical linux-gcp-5.11 All versions
Showing 50 of 176. Show the rest
Ecosystem VendorProductAffected versions
Ubuntu:20.04:LTS canonical linux-gcp-5.13 All versions
Ubuntu:Pro:20.04:LTS canonical linux-gcp-5.15 All versions
Ubuntu:20.04:LTS canonical linux-gcp-5.8 All versions
Ubuntu:20.04:LTS canonical linux-gke All versions
Ubuntu:20.04:LTS canonical linux-gke-5.15 All versions
Ubuntu:20.04:LTS canonical linux-gkeop All versions
Ubuntu:20.04:LTS canonical linux-gkeop-5.15 All versions
Ubuntu:20.04:LTS canonical linux-hwe-5.11 All versions
Ubuntu:20.04:LTS canonical linux-hwe-5.13 All versions
Ubuntu:Pro:20.04:LTS canonical linux-hwe-5.15 All versions
Ubuntu:20.04:LTS canonical linux-hwe-5.8 All versions
Ubuntu:Pro:20.04:LTS canonical linux-ibm All versions
Ubuntu:Pro:20.04:LTS canonical linux-ibm-5.15 All versions
Ubuntu:20.04:LTS canonical linux-intel-5.13 All versions
Ubuntu:Pro:20.04:LTS canonical linux-intel-iotg-5.15 All versions
Ubuntu:Pro:20.04:LTS canonical linux-iot All versions
Ubuntu:Pro:20.04:LTS canonical linux-lowlatency-hwe-5.15 All versions
Ubuntu:Pro:20.04:LTS canonical linux-nvidia-tegra-5.15 All versions
Ubuntu:20.04:LTS canonical linux-oem-5.10 All versions
Ubuntu:20.04:LTS canonical linux-oem-5.13 All versions
Ubuntu:20.04:LTS canonical linux-oem-5.14 All versions
Ubuntu:20.04:LTS canonical linux-oem-5.6 All versions
Ubuntu:20.04:LTS canonical linux-oracle-5.11 All versions
Ubuntu:20.04:LTS canonical linux-oracle-5.13 All versions
Ubuntu:Pro:20.04:LTS canonical linux-oracle-5.15 All versions
Ubuntu:20.04:LTS canonical linux-oracle-5.8 All versions
Ubuntu:Pro:20.04:LTS canonical linux-raspi All versions
Ubuntu:20.04:LTS canonical linux-raspi2 All versions
Ubuntu:20.04:LTS canonical linux-riscv All versions
Ubuntu:20.04:LTS canonical linux-riscv-5.11 All versions
Ubuntu:Pro:20.04:LTS canonical linux-riscv-5.15 All versions
Ubuntu:20.04:LTS canonical linux-riscv-5.8 All versions
Ubuntu:Pro:20.04:LTS canonical linux-xilinx-zynqmp All versions
Ubuntu:22.04:LTS canonical linux-allwinner-5.19 All versions
Ubuntu:22.04:LTS canonical linux-aws-5.19 All versions
Ubuntu:22.04:LTS canonical linux-aws-6.2 All versions
Ubuntu:22.04:LTS canonical linux-aws-6.5 All versions
Ubuntu:22.04:LTS canonical linux-aws-6.8 All versions
Ubuntu:22.04:LTS canonical linux-azure-5.19 All versions
Ubuntu:22.04:LTS canonical linux-azure-6.2 All versions
Ubuntu:22.04:LTS canonical linux-azure-6.5 All versions
Ubuntu:22.04:LTS canonical linux-azure-6.8 All versions
Ubuntu:22.04:LTS canonical linux-azure-fde-5.19 All versions
Ubuntu:22.04:LTS canonical linux-azure-fde-6.2 All versions
Ubuntu:22.04:LTS canonical linux-azure-fde-6.8 All versions
Ubuntu:22.04:LTS canonical linux-gcp-5.19 All versions
Ubuntu:22.04:LTS canonical linux-gcp-6.2 All versions
Ubuntu:22.04:LTS canonical linux-gcp-6.5 All versions
Ubuntu:22.04:LTS canonical linux-gcp-6.8 All versions
Ubuntu:22.04:LTS canonical linux-hwe-5.19 All versions
Ubuntu:22.04:LTS canonical linux-hwe-6.2 All versions
Ubuntu:22.04:LTS canonical linux-hwe-6.5 All versions
Ubuntu:22.04:LTS canonical linux-hwe-6.8 All versions
Ubuntu:22.04:LTS canonical linux-ibm-6.8 All versions
Ubuntu:22.04:LTS canonical linux-intel-iot-realtime All versions
Ubuntu:22.04:LTS canonical linux-intel-iotg All versions
Ubuntu:22.04:LTS canonical linux-lowlatency All versions
Ubuntu:22.04:LTS canonical linux-lowlatency-hwe-5.19 All versions
Ubuntu:22.04:LTS canonical linux-lowlatency-hwe-6.2 All versions
Ubuntu:22.04:LTS canonical linux-lowlatency-hwe-6.5 All versions
Ubuntu:22.04:LTS canonical linux-lowlatency-hwe-6.8 All versions
Ubuntu:22.04:LTS canonical linux-nvidia All versions
Ubuntu:22.04:LTS canonical linux-nvidia-6.2 All versions
Ubuntu:22.04:LTS canonical linux-nvidia-6.5 All versions
Ubuntu:22.04:LTS canonical linux-nvidia-6.8 All versions
Ubuntu:22.04:LTS canonical linux-nvidia-tegra All versions
Ubuntu:22.04:LTS canonical linux-nvidia-tegra-igx All versions
Ubuntu:22.04:LTS canonical linux-oem-5.17 All versions
Ubuntu:22.04:LTS canonical linux-oem-6.0 All versions
Ubuntu:22.04:LTS canonical linux-oem-6.1 All versions
Ubuntu:22.04:LTS canonical linux-oem-6.5 All versions
Ubuntu:22.04:LTS canonical linux-oracle-6.5 All versions
Ubuntu:22.04:LTS canonical linux-oracle-6.8 All versions
Ubuntu:22.04:LTS canonical linux-realtime All versions
Ubuntu:22.04:LTS canonical linux-riscv-5.19 All versions
Ubuntu:22.04:LTS canonical linux-riscv-6.5 All versions
Ubuntu:22.04:LTS canonical linux-riscv-6.8 All versions
Ubuntu:22.04:LTS canonical linux-starfive-5.19 All versions
Ubuntu:22.04:LTS canonical linux-starfive-6.2 All versions
Ubuntu:22.04:LTS canonical linux-starfive-6.5 All versions
Ubuntu:Pro:Realtime:22.04:LTS canonical linux-realtime-6.8 All versions
Ubuntu:24.04:LTS canonical linux-aws-6.14 All versions
Ubuntu:24.04:LTS canonical linux-aws-6.17 All versions
Ubuntu:24.04:LTS canonical linux-aws-7.0 All versions
Ubuntu:24.04:LTS canonical linux-azure-6.11 All versions
Ubuntu:24.04:LTS canonical linux-azure-6.14 All versions
Ubuntu:24.04:LTS canonical linux-azure-6.17 All versions
Ubuntu:24.04:LTS canonical linux-azure-7.0 All versions
Ubuntu:24.04:LTS canonical linux-azure-fde-6.14 All versions
Ubuntu:24.04:LTS canonical linux-azure-fde-6.17 All versions
Ubuntu:24.04:LTS canonical linux-azure-fde-7.0 All versions
Ubuntu:24.04:LTS canonical linux-azure-nvidia All versions
Ubuntu:24.04:LTS canonical linux-azure-nvidia-6.14 All versions
Ubuntu:24.04:LTS canonical linux-gcp-6.11 All versions
Ubuntu:24.04:LTS canonical linux-gcp-6.14 All versions
Ubuntu:24.04:LTS canonical linux-gcp-6.17 All versions
Ubuntu:24.04:LTS canonical linux-gcp-7.0 All versions
Ubuntu:24.04:LTS canonical linux-hwe-6.11 All versions
Ubuntu:24.04:LTS canonical linux-hwe-6.14 All versions
Ubuntu:24.04:LTS canonical linux-hwe-6.17 All versions
Ubuntu:24.04:LTS canonical linux-hwe-7.0 All versions
Ubuntu:24.04:LTS canonical linux-lowlatency-hwe-6.11 All versions
Ubuntu:24.04:LTS canonical linux-nvidia-6.11 All versions
Ubuntu:24.04:LTS canonical linux-nvidia-6.17 All versions
Ubuntu:24.04:LTS canonical linux-nvidia-7.0 All versions
Ubuntu:24.04:LTS canonical linux-nvidia-lowlatency All versions
Ubuntu:24.04:LTS canonical linux-oem-6.11 All versions
Ubuntu:24.04:LTS canonical linux-oem-6.14 All versions
Ubuntu:24.04:LTS canonical linux-oem-6.17 All versions
Ubuntu:24.04:LTS canonical linux-oem-6.8 All versions
Ubuntu:24.04:LTS canonical linux-oracle-6.14 All versions
Ubuntu:24.04:LTS canonical linux-oracle-6.17 All versions
Ubuntu:24.04:LTS canonical linux-oracle-7.0 All versions
Ubuntu:24.04:LTS canonical linux-raspi-realtime All versions
Ubuntu:24.04:LTS canonical linux-riscv-6.14 All versions
Ubuntu:24.04:LTS canonical linux-riscv-6.17 All versions
Ubuntu:24.04:LTS canonical linux-riscv-7.0 All versions
Ubuntu:24.04:LTS canonical linux-xilinx All versions
Ubuntu:Pro:Realtime:24.04:LTS canonical linux-realtime-6.14 All versions
Ubuntu:Pro:Realtime:24.04:LTS canonical linux-realtime-6.17 All versions
Ubuntu:26.04:LTS canonical linux-nvidia-bos All versions
Ubuntu:26.04:LTS canonical linux-oem-7.0 All versions
Alpaquita:23 bellsoft linux-lts >= 6.1.182-r0
Alpaquita:25 bellsoft linux-lts >= 6.12.103-r0
Alpaquita:stream bellsoft linux-lts >= 6.18.46-r0
Ubuntu:24.04:LTS canonical linux-vmware All versions
Original advisory text
ceph: fix UAF in check_new_map() on session freed during unlock
In the Linux kernel, the following vulnerability has been resolved: ceph: fix UAF in check_new_map() on session freed during unlock check_new_map() iterates mdsc->sessions[] and for each active session drops mdsc->mutex to perform per-session operations. The forced-close path (rank removed from map) correctly takes a reference on s via ceph_get_mds_session() before releasing mdsc->mutex, but three other paths do not: Path A (address changed): mutex_unlock → mutex_lock(&s->s_mutex) Path B (reconnect): mutex_unlock → send_mds_reconnect(mdsc, s) Path C (active transition): mutex_unlock → mutex_lock(&s->s_mutex) Without the extra reference, another thread can acquire mdsc->mutex during the unlock window, call __unregister_session() which drops the last reference on s, and free it. The original thread then accesses freed memory via s->s_mutex. Fix by adding ceph_get_mds_session(s) before each mutex_unlock and ceph_put_mds_session(s) after the corresponding mutex_lock, matching the pattern already used in the forced-close path. Race timeline (Path A): Thread A (check_new_map) Thread B (another map update holds mdsc->mutex or session teardown) -------------------------- -------------------------- s = mdsc->sessions[i] (refcount == 1, held only by sessions[] array) mutex_unlock(&mdsc->mutex) ---> acquires mdsc->mutex __unregister_session(mdsc, s) sessions[i] = NULL ceph_put_mds_session(s) refcount: 1 -> 0 kfree(s) <--- freed! mutex_lock(&s->s_mutex) UAF on freed s->s_mutex
Severity
9.8 Critical
Exploitation
<1% chance of attack within 30 days
Timeline
Published11 Sep 2026
Updated12 Oct 2026
First seen11 Sep 2026
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