CVE-2026-74597: In the Linux kernel, the following vulnerability has been resolved: ip6_tunnel: clear skb2->cb[] in ip6ip6_er

This month

CRITICAL 9.8REMOTEWATCHLIST

CVE-2026-74597 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: ip6_tunnel: clear skb2->cb[] in ip6ip6_err() ip6ip6_err() clones an outer IPv6 ICMP error skb, pulls it to the quoted inner IPv6 packet, and then passes the clone to icmpv6_send(). The clone still carries the outer packet's inet6_skb_parm in skb->cb. If the outer packet had a Home Address Option, IP6CB(skb2)->dsthao remains non-zero after skb_pull(). icmpv6_send() later calls

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	0.5% (top 55%)
CISA exploited list	No
Published	2026-08-22
Last modified	2026-10-16

Publisher (CNA): kernel.org

Last updated 2026-10-16 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Timeline

2026-08-22 16:16 UTCPublished CVE record published
2026-10-16 20:17 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 20.04 · linux · NO FIX YET

Ubuntu 24.04 · linux · NO FIX YET

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 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 · 6.1.187-1

sudo apt update && sudo apt install --only-upgrade linux dpkg --compare-versions "$(dpkg-query -W -f='${Version}' linux)" ge "6.1.187-1" && echo PATCHED || echo STILL-VULNERABLE

Debian 13 · linux · FIXED · 6.12.105-1

sudo apt update && sudo apt install --only-upgrade linux dpkg --compare-versions "$(dpkg-query -W -f='${Version}' linux)" ge "6.12.105-1" && echo PATCHED || echo STILL-VULNERABLE

Debian 12 · linux-6.12 · FIXED · 6.12.107-1~deb12u1

sudo apt update && sudo apt install --only-upgrade linux-6.12 dpkg --compare-versions "$(dpkg-query -W -f='${Version}' linux-6.12)" ge "6.12.107-1~deb12u1" && echo PATCHED || echo STILL-VULNERABLE

RHEL 10 · kernel · NO FIX YET

RHEL 6 · kernel · NOT AFFECTED

RHEL 7 · kernel · NO FIX YET

RHEL 7 · kernel-rt · NO FIX YET

RHEL 8 · kernel · NO FIX YET

Amazon Linux 2023 · see advisory · FIXED · ALAS2023-2026-3196 · source

sudo dnf update --advisory=ALAS2023-2026-3196

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-2026-74597?

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

Is CVE-2026-74597 being exploited?

CVE-2026-74597 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-2026-74597 affect?

CVE-2026-74597 affects affected software. Severity is critical (CVSS 9.8). In the Linux kernel, the following vulnerability has been resolved: ip6_tunnel: clear skb2->cb[] in ip6ip6_err() ip6ip6_err() clones an outer IPv6 ICMP error skb, pulls it to the quoted inner IPv6 packet, and then passes the clone to icmp

How urgent is CVE-2026-74597?

Priority 56/100. Critical severity; Remotely exploitable, no login, no user action; On your watchlist

Software pages

Linux kernel vulnerabilities

References

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