CVE-2026-64535: In the Linux kernel, the following vulnerability has been resolved: nvmet-tcp: Fix potential UAF when ddgst m

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CRITICAL 9.8REMOTEWATCHLIST

CVE-2026-64535 is a critical-severity flaw (CVSS 9.8) affecting affected software. 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: nvmet-tcp: Fix potential UAF when ddgst mismatch Shivam Kumar found via vulnerability testing: When data digest is enabled on an NVMe/TCP connection and a digest mismatch occurs on a non-final H2C_DATA PDU during an R2T-based data transfer, the digest error handler in nvmet_tcp_try_recv_ddgst() calls nvmet_req_uninit() — which performs percpu_ref_put() on the submission queue —

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 score	9.8 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.5% (top 54%)
CISA exploited list	No
Weakness	CWE-415
Published	2026-07-27
Last modified	2026-10-19

Publisher (CNA): kernel.org

Last updated 2026-10-19 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Timeline

2026-07-27 08:16 UTCPublished CVE record published
2026-10-19 21:17 UTCUpdated Record last modified

Exact fixes by distribution

Fedora 46 · gcl · FIXED · 2.7.1-12.fc46 · FEDORA-2026-ff383a759b · source

sudo dnf upgrade --advisory=FEDORA-2026-ff383a759b

Fedora ELN · mozjs140 · FIXED · 140.13.0-5.eln159 · FEDORA-2026-f7ed0026e0 · source

sudo dnf upgrade --advisory=FEDORA-2026-f7ed0026e0

Ubuntu 22.04 · linux · FIXED · 5.15.0-198.208

sudo apt update && sudo apt install --only-upgrade linux dpkg --compare-versions "$(dpkg-query -W -f='${Version}' linux)" ge "5.15.0-198.208" && echo PATCHED || echo STILL-VULNERABLE

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 · NOT AFFECTED

Ubuntu 20.04 · linux-hwe-5.15 · FIXED · 5.15.0-198.208~20.04.1

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 "5.15.0-198.208~20.04.1" && echo PATCHED || echo STILL-VULNERABLE

Ubuntu 22.04 · linux-hwe-6.8 · NO FIX YET

Debian 12 · linux · FIXED · 6.1.180-1

sudo apt update && sudo apt install --only-upgrade linux dpkg --compare-versions "$(dpkg-query -W -f='${Version}' linux)" ge "6.1.180-1" && echo PATCHED || echo STILL-VULNERABLE

Debian 13 · linux · FIXED · 6.12.100-1

sudo apt update && sudo apt install --only-upgrade linux dpkg --compare-versions "$(dpkg-query -W -f='${Version}' linux)" ge "6.12.100-1" && echo PATCHED || echo STILL-VULNERABLE

Debian 12 · linux-6.12 · FIXED · 6.12.100-1~deb12u1

sudo apt update && sudo apt install --only-upgrade linux-6.12 dpkg --compare-versions "$(dpkg-query -W -f='${Version}' linux-6.12)" ge "6.12.100-1~deb12u1" && echo PATCHED || echo STILL-VULNERABLE

RHEL 10 · kernel · DEFERRED

RHEL 10 · libkrun · NOT AFFECTED

RHEL 6 · kernel · NOT AFFECTED

RHEL 7 · kernel · NOT AFFECTED

RHEL 7 · kernel-rt · NOT AFFECTED

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-2026-64535?

No fixed release is listed yet. Watch the vendor advisory and apply any mitigation shown on this page.

Is CVE-2026-64535 being exploited?

CVE-2026-64535 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-2026-64535 affect?

CVE-2026-64535 affects affected software. Severity is critical (CVSS 9.8). In the Linux kernel, the following vulnerability has been resolved: nvmet-tcp: Fix potential UAF when ddgst mismatch Shivam Kumar found via vulnerability testing: When data digest is enabled on an NVMe/TCP connection and a digest mismatch

How urgent is CVE-2026-64535?

Priority 59/100. Critical severity; CISA SSVC: automatable with total technical impact; Remotely exploitable, no login, no user action; On your watchlist

Software pages

Linux kernel vulnerabilities

References

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