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CVE-2026-63808: In the Linux kernel, the following vulnerability has been resolved: exfat: fix potential use-after-free in ex

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CRITICAL 9.8REMOTEWATCHLISTUPGRADE

CVE-2026-63808 is a critical-severity flaw (CVSS 9.8) affecting linux kernel. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

In the Linux kernel, the following vulnerability has been resolved: exfat: fix potential use-after-free in exfat_find_dir_entry() In exfat_find_dir_entry(), the buffer_head obtained from exfat_get_dentry() is released with brelse(bh) before the fall-through TYPE_EXTEND branch reads the directory entry through ep (which points into bh->b_data): brelse(bh); if (entry_type == TYPE_EXTEND) { ... len = exfat_extract_uni_name(ep, entry_uniname

Why this priority

  • Critical severity
  • CISA SSVC: automatable with total technical impact
  • Remotely exploitable, no login, no user action
  • On your watchlist

A fixed release or distro patch exists.

Risk facts

CVSS score9.8 (Critical)
Attack vectorNetwork (remote)
Attack complexityLow
Privileges neededNone
User interactionNone
EPSS exploit chance0.5% (top 56%)
CISA exploited listNo
WeaknessCWE-416
Published2026-07-19
Last modified2026-10-22
Publisher (CNA): kernel.org · Vendor: linux

Last updated 2026-10-22 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

linux linux kernel UPGRADE
Affected: >= 5.7 and < 5.10.260 · >= 5.11 and < 5.15.211 · >= 5.16 and < 6.1.177 · >= 6.2 and < 6.6.144 · >= 6.7 and < 6.12.95 · >= 6.13 and < 6.18.38 · >= 6.19 and < 7.1.3
Fixed in: 5.10.260, 5.15.211, 6.1.177, 6.6.144, 6.12.95, 6.18.38, 7.1.3
Safe to downgrade to: no unaffected older release
Check your OS release
cat /etc/os-release; uname -r
Debian / Ubuntu
sudo apt update && sudo apt full-upgrade
RHEL / Amazon Linux / Fedora
sudo dnf upgrade --refresh
Windows
Install the latest cumulative update from Windows Update
If no patch exists yet
OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

Exact fixes by distribution

Fedora 46 · python-streamlink · FIXED · 8.6.2-1.fc46 · FEDORA-2026-a56fcfdc08 · source
sudo dnf upgrade --advisory=FEDORA-2026-a56fcfdc08
Fedora ELN · valgrind · FIXED · 3.28.0-1.eln159 · FEDORA-2026-c593ef1d15 · source
sudo dnf upgrade --advisory=FEDORA-2026-c593ef1d15
Ubuntu 22.04 · linux · FIXED · 5.15.0-194.204
sudo apt update && sudo apt install --only-upgrade linux dpkg --compare-versions "$(dpkg-query -W -f='${Version}' linux)" ge "5.15.0-194.204" && echo PATCHED || echo STILL-VULNERABLE
Ubuntu 20.04 · linux · NOT AFFECTED
Ubuntu 24.04 · linux · FIXED · 6.8.0-147.147
sudo apt update && sudo apt install --only-upgrade linux dpkg --compare-versions "$(dpkg-query -W -f='${Version}' linux)" ge "6.8.0-147.147" && echo PATCHED || echo STILL-VULNERABLE
Ubuntu 20.04 · linux-hwe-5.15 · FIXED · 5.15.0-194.204~20.04.1
sudo apt update && sudo apt install --only-upgrade linux-hwe-5.15 dpkg --compare-versions "$(dpkg-query -W -f='${Version}' linux-hwe-5.15)" ge "5.15.0-194.204~20.04.1" && echo PATCHED || echo STILL-VULNERABLE
Ubuntu 22.04 · linux-hwe-6.8 · NO FIX YET
Debian 12 · linux · FIXED · 6.1.177-1
sudo apt update && sudo apt install --only-upgrade linux dpkg --compare-versions "$(dpkg-query -W -f='${Version}' linux)" ge "6.1.177-1" && echo PATCHED || echo STILL-VULNERABLE
Debian 13 · linux · FIXED · 6.12.95-1
sudo apt update && sudo apt install --only-upgrade linux dpkg --compare-versions "$(dpkg-query -W -f='${Version}' linux)" ge "6.12.95-1" && echo PATCHED || echo STILL-VULNERABLE
RHEL 10 · kernel · FIXED · kernel-6.12.0-211.51.1.el10_2
sudo dnf upgrade --advisory=RHSA-2026:63128 rpm -q kernel
RHEL 9 · kernel · FIXED · kernel-5.14.0-687.44.1.el9_8
sudo dnf upgrade --advisory=RHSA-2026:63129 rpm -q kernel
RHEL 6 · kernel · NOT AFFECTED
RHEL 7 · kernel · NOT AFFECTED
RHEL 7 · kernel-rt · NOT AFFECTED
Amazon Linux 2023 · see advisory · FIXED · ALAS2023-2026-2032 · source
sudo dnf update --advisory=ALAS2023-2026-2032
Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-63808?

linux kernel: upgrade to 5.10.260, 5.15.211, 6.1.177, 6.6.144, 6.12.95, 6.18.38, 7.1.3. Exact commands for each OS are on this page.

Is CVE-2026-63808 being exploited?

CVE-2026-63808 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-63808 affect?

CVE-2026-63808 affects linux kernel. Severity is critical (CVSS 9.8). In the Linux kernel, the following vulnerability has been resolved: exfat: fix potential use-after-free in exfat_find_dir_entry() In exfat_find_dir_entry(), the buffer_head obtained from exfat_get_dentry() is released with brelse(bh) befo

How urgent is CVE-2026-63808?

Priority 58/100. Critical severity; CISA SSVC: automatable with total technical impact; Remotely exploitable, no login, no user action; On your watchlist

Software pages

Linux kernel vulnerabilities

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References

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