CVE-2026-74478: In the Linux kernel, the following vulnerability has been resolved: um: vector: fix use-after-free in vector_

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CRITICAL 9.8REMOTEWATCHLIST

CVE-2026-74478 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: um: vector: fix use-after-free in vector_mmsg_rx() When vector_mmsg_rx() discards a packet whose overlay header fails verify_header(), it frees the skb and continues the loop: if (header_check < 0) { dev_kfree_skb_irq(skb); vp->estats.rx_encaps_errors++; continue; } The normal and short-packet paths fall through to the bottom of the loop body, which clears the consume

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	0.9% (top 42%)
CISA exploited list	No
Published	2026-08-15
Last modified	2026-08-19

Publisher (CNA): kernel.org

Last updated 2026-08-19 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Timeline

2026-08-15 13:17 UTCPublished CVE record published
2026-08-19 17:21 UTCUpdated Record last modified

Exact fixes by distribution

Fedora ELN · openbao · FIXED · 2.6.5-1.eln159 · FEDORA-2026-77adf886ae · source

sudo dnf upgrade --advisory=FEDORA-2026-77adf886ae

Fedora 46 · sugar-turtleart · FIXED · 220-16.fc46 · FEDORA-2026-b79483c788 · source

sudo dnf upgrade --advisory=FEDORA-2026-b79483c788

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 · NOT AFFECTED

RHEL 6 · kernel · NOT AFFECTED

RHEL 7 · kernel · NOT AFFECTED

RHEL 7 · kernel-rt · NOT AFFECTED

RHEL 8 · kernel · 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-2026-74478?

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

Is CVE-2026-74478 being exploited?

CVE-2026-74478 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-2026-74478 affect?

CVE-2026-74478 affects affected software. Severity is critical (CVSS 9.8). In the Linux kernel, the following vulnerability has been resolved: um: vector: fix use-after-free in vector_mmsg_rx() When vector_mmsg_rx() discards a packet whose overlay header fails verify_header(), it frees the skb and continues the

How urgent is CVE-2026-74478?

Priority 59/100. Critical severity; Remotely exploitable, no login, no user action; On your watchlist

Software pages

Linux kernel vulnerabilities

References

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