CVE-2026-63888: In the Linux kernel, the following vulnerability has been resolved: scsi: target: iscsi: Fix CRC overread and

Q: How do I fix CVE-2026-63888?

linux kernel: upgrade to 5.10.259, 5.15.210, 6.1.176, 6.6.143, 6.12.93, 6.18.35, 7.0.12. Exact commands for each OS are on this page.

Q: Is CVE-2026-63888 being exploited?

CVE-2026-63888 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2026-63888 affect?

CVE-2026-63888 affects linux kernel. Severity is critical (CVSS 9.8). In the Linux kernel, the following vulnerability has been resolved: scsi: target: iscsi: Fix CRC overread and double-free in iscsit_handle_text_cmd() Two latent bugs in the Text-phase handler, both present since the original LIO integrati

Q: How urgent is CVE-2026-63888?

Priority 58/100. Critical severity; Remotely exploitable, no login, no user action; On your watchlist

This month

CRITICAL 9.8REMOTEWATCHLISTUPGRADE

CVE-2026-63888 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: scsi: target: iscsi: Fix CRC overread and double-free in iscsit_handle_text_cmd() Two latent bugs in the Text-phase handler, both present since the original LIO integration in commit e48354ce078c ("iscsi-target: Add iSCSI fabric support for target v4.1"): 1) DataDigest CRC buffer overread (4 bytes past text_in). text_in is kzalloc()'d at ALIGN(payload_length, 4). rx_size

Why this priority

Critical severity
Remotely exploitable, no login, no user action
On your watchlist

A fixed release or distro patch exists.

Risk facts

CVSS score	9.8 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.8% (top 44%)
CISA exploited list	No
Weakness	CWE-415
Published	2026-07-19
Last modified	2026-10-26

Publisher (CNA): kernel.org · Vendor: linux

Last updated 2026-10-26 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-07-19 16:17 UTCPublished CVE record published
2026-10-26 20:17 UTCUpdated Record last modified

linux linux kernel UPGRADE

Affected: >= 3.1 and < 5.10.259 · >= 5.11 and < 5.15.210 · >= 5.16 and < 6.1.176 · >= 6.2 and < 6.6.143 · >= 6.7 and < 6.12.93 · >= 6.13 and < 6.18.35 · >= 6.19 and < 7.0.12 · 7.1 rc1

Fixed in: 5.10.259, 5.15.210, 6.1.176, 6.6.143, 6.12.93, 6.18.35, 7.0.12

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 · ddnet · FIXED · 20.2-1.fc46 · FEDORA-2026-6991b4ab14 · source

sudo dnf upgrade --advisory=FEDORA-2026-6991b4ab14

Fedora ELN · libplacebo · FIXED · 7.360.1-5.eln159 · FEDORA-2026-92226f221e · source

sudo dnf upgrade --advisory=FEDORA-2026-92226f221e

Debian 12 · linux · FIXED · 6.1.176-1

sudo apt update && sudo apt install --only-upgrade linux dpkg --compare-versions "$(dpkg-query -W -f='${Version}' linux)" ge "6.1.176-1" && echo PATCHED || echo STILL-VULNERABLE

Debian 13 · linux · FIXED · 6.12.94-1

sudo apt update && sudo apt install --only-upgrade linux dpkg --compare-versions "$(dpkg-query -W -f='${Version}' linux)" ge "6.12.94-1" && echo PATCHED || echo STILL-VULNERABLE

RHEL 10 · kernel · FIXED · kernel-6.12.0-211.49.1.el10_2

sudo dnf upgrade --advisory=RHSA-2026:57251 rpm -q kernel

RHEL 10.0 Extended Update Support · kernel · FIXED · kernel-6.12.0-55.105.1.el10_0

sudo dnf upgrade --advisory=RHSA-2026:69089 rpm -q kernel

RHEL 8 · kernel-rt · FIXED · kernel-rt-4.18.0-553.157.1.rt7.498.el8_10

sudo dnf upgrade --advisory=RHSA-2026:57254 rpm -q kernel-rt

RHEL 8 · kernel · FIXED · kernel-4.18.0-553.157.1.el8_10

sudo dnf upgrade --advisory=RHSA-2026:57253 rpm -q kernel

RHEL 8.4 Advanced Mission Critical Update Support · kernel · FIXED · kernel-4.18.0-305.208.1.el8_4

sudo dnf upgrade --advisory=RHSA-2026:69874 rpm -q kernel

Amazon Linux 2023 · see advisory · FIXED · ALAS2023-2026-1968 · source

sudo dnf update --advisory=ALAS2023-2026-1968

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-2026-63888?

linux kernel: upgrade to 5.10.259, 5.15.210, 6.1.176, 6.6.143, 6.12.93, 6.18.35, 7.0.12. Exact commands for each OS are on this page.

Is CVE-2026-63888 being exploited?

CVE-2026-63888 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-2026-63888 affect?

CVE-2026-63888 affects linux kernel. Severity is critical (CVSS 9.8). In the Linux kernel, the following vulnerability has been resolved: scsi: target: iscsi: Fix CRC overread and double-free in iscsit_handle_text_cmd() Two latent bugs in the Text-phase handler, both present since the original LIO integrati

How urgent is CVE-2026-63888?

Priority 58/100. Critical severity; Remotely exploitable, no login, no user action; On your watchlist

Software pages

Linux kernel vulnerabilities

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References

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