CVE-2026-43493: In the Linux kernel, the following vulnerability has been resolved: crypto: pcrypt - Fix handling of MAY_BACK

Q: How do I fix CVE-2026-43493?

linux kernel: upgrade to 5.10.258, 5.15.209, 6.1.175, 6.6.140, 6.12.86, 6.18.27, 7.0.4. Exact commands for each OS are on this page.

Q: Is CVE-2026-43493 being exploited?

CVE-2026-43493 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-2026-43493 affect?

CVE-2026-43493 affects linux kernel. Severity is critical (CVSS 9.8). In the Linux kernel, the following vulnerability has been resolved: crypto: pcrypt - Fix handling of MAY_BACKLOG requests MAY_BACKLOG requests can return EBUSY. Handle them by checking for that value and filtering out EINPROGRESS notific

Q: How urgent is CVE-2026-43493?

Priority 60/100. Critical severity; CISA SSVC: automatable with total technical impact; Remotely exploitable, no login, no user action; On your watchlist

This week

CRITICAL 9.8REMOTEWATCHLISTUPGRADE

CVE-2026-43493 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: crypto: pcrypt - Fix handling of MAY_BACKLOG requests MAY_BACKLOG requests can return EBUSY. Handle them by checking for that value and filtering out EINPROGRESS notifications.

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	0.7% (top 48%)
CISA exploited list	No
Weakness	CWE-390
Published	2026-05-19
Last modified	2026-10-19

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

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

Am I affected?

Timeline

2026-05-19 12:16 UTCPublished CVE record published
2026-10-19 20:18 UTCUpdated Record last modified

linux linux kernel UPGRADE

Affected: >= 2.6.34 and < 5.10.258 · >= 5.11 and < 5.15.209 · >= 5.16 and < 6.1.175 · >= 6.2 and < 6.6.140 · >= 6.7 and < 6.12.86 · >= 6.13 and < 6.18.27 · >= 6.19 and < 7.0.4

Fixed in: 5.10.258, 5.15.209, 6.1.175, 6.6.140, 6.12.86, 6.18.27, 7.0.4

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 · proftpd · FIXED · 1.3.9e-1.fc46 · FEDORA-2026-fc0d87d66e · source

sudo dnf upgrade --advisory=FEDORA-2026-fc0d87d66e

Ubuntu 20.04 · linux · FIXED · 5.4.0-234.254

sudo apt update && sudo apt install --only-upgrade linux dpkg --compare-versions "$(dpkg-query -W -f='${Version}' linux)" ge "5.4.0-234.254" && echo PATCHED || echo STILL-VULNERABLE

Ubuntu 22.04 · linux · FIXED · 5.15.0-185.195

sudo apt update && sudo apt install --only-upgrade linux dpkg --compare-versions "$(dpkg-query -W -f='${Version}' linux)" ge "5.15.0-185.195" && echo PATCHED || echo STILL-VULNERABLE

Ubuntu 25.10 · linux · FIXED · 6.17.0-40.40

sudo apt update && sudo apt install --only-upgrade linux dpkg --compare-versions "$(dpkg-query -W -f='${Version}' linux)" ge "6.17.0-40.40" && echo PATCHED || echo STILL-VULNERABLE

Ubuntu 24.04 · linux · FIXED · 6.8.0-134.134

sudo apt update && sudo apt install --only-upgrade linux dpkg --compare-versions "$(dpkg-query -W -f='${Version}' linux)" ge "6.8.0-134.134" && echo PATCHED || echo STILL-VULNERABLE

Ubuntu 20.04 · linux-hwe-5.15 · FIXED · 5.15.0-185.195~20.04.1

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 "5.15.0-185.195~20.04.1" && echo PATCHED || echo STILL-VULNERABLE

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 · 6.12.86-1

sudo apt update && sudo apt install --only-upgrade linux dpkg --compare-versions "$(dpkg-query -W -f='${Version}' linux)" ge "6.12.86-1" && 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-6.12.0-55.108.1.el10_0

sudo dnf upgrade --advisory=RHSA-2026:75560 rpm -q kernel

RHEL 8 · kernel-rt · FIXED · kernel-rt-4.18.0-553.160.1.rt7.501.el8_10

sudo dnf upgrade --advisory=RHSA-2026:64770 rpm -q kernel-rt

RHEL 8 · kernel · FIXED · kernel-4.18.0-553.160.1.el8_10

sudo dnf upgrade --advisory=RHSA-2026:66000 rpm -q kernel

RHEL 8.6 Advanced Mission Critical Update Support · kernel · FIXED · kernel-4.18.0-372.223.1.el8_6

sudo dnf upgrade --advisory=RHSA-2026:85000 rpm -q kernel

Amazon Linux 2023 · see advisory · FIXED · ALAS2023-2026-1882 · source

sudo dnf update --advisory=ALAS2023-2026-1882

Public exploits and detection

Public code exists for this CVE. Treat unpatched systems as at risk, and only run PoCs in a lab.

Write-up: cert-portal.siemens.com/productcert/html/ssa-784472.html

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-2026-43493?

linux kernel: upgrade to 5.10.258, 5.15.209, 6.1.175, 6.6.140, 6.12.86, 6.18.27, 7.0.4. Exact commands for each OS are on this page.

Is CVE-2026-43493 being exploited?

CVE-2026-43493 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-2026-43493 affect?

CVE-2026-43493 affects linux kernel. Severity is critical (CVSS 9.8). In the Linux kernel, the following vulnerability has been resolved: crypto: pcrypt - Fix handling of MAY_BACKLOG requests MAY_BACKLOG requests can return EBUSY. Handle them by checking for that value and filtering out EINPROGRESS notific

How urgent is CVE-2026-43493?

Priority 60/100. Critical severity; CISA SSVC: automatable with total technical impact; Remotely exploitable, no login, no user action; On your watchlist

Software pages

Linux kernel vulnerabilities

Related CVEs

CVE-2026-98141 MEDIUM 5.5 UPGRADE In the Linux kernel, the following vulnerability has been resolved: ntfs: propagate reparse index insertion f
CVE-2026-64239 HIGH 7.8 UPGRADE In the Linux kernel, the following vulnerability has been resolved: mm/damon/sysfs-schemes: delete tried regi
CVE-2026-64236 MEDIUM 5.5 UPGRADE In the Linux kernel, the following vulnerability has been resolved: i2c: davinci: fix division by zero on mis
CVE-2026-98142 MEDIUM 5.5 UPGRADE In the Linux kernel, the following vulnerability has been resolved: drm/cirrus-qemu: Validate BAR0 size durin
CVE-2026-98147 MEDIUM 5.5 UPGRADE In the Linux kernel, the following vulnerability has been resolved: printk: Don't WARN on kthread_run failure

References

← Back to latest CVEs