CVE-2026-66311: Missing authorization in Microsoft Edge (Chromium-based) allows an unauthorized attacker to perform tampering

Q: How do I fix CVE-2026-66311?

edge chromium: upgrade to 151.0.4129.59. Exact commands for each OS are on this page.

Q: Is CVE-2026-66311 being exploited?

CVE-2026-66311 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-2026-66311 affect?

CVE-2026-66311 affects edge chromium. Severity is medium (CVSS 6.2). Missing authorization in Microsoft Edge (Chromium-based) allows an unauthorized attacker to perform tampering locally.

Q: How urgent is CVE-2026-66311?

Priority 35/100. On your watchlist

Routine

MEDIUM 6.2WATCHLISTUPGRADE

CVE-2026-66311 is a medium-severity flaw (CVSS 6.2) affecting edge chromium. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Missing authorization in Microsoft Edge (Chromium-based) allows an unauthorized attacker to perform tampering locally.

Why this priority

On your watchlist

A fixed release or distro patch exists.

Risk facts

CVSS score	6.2 (Medium)
Attack vector	Local
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.4% (top 66%)
CISA exploited list	No
Weakness	CWE-862
Published	2026-08-04
Last modified	2026-10-23

Publisher (CNA): Microsoft Corporation · Vendor: microsoft

Last updated 2026-10-23 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-08-04 00:17 UTCPublished CVE record published
2026-10-23 23:10 UTCUpdated Record last modified

microsoft edge chromium UPGRADE

Affected: < 151.0.4129.59

Fixed in: 151.0.4129.59

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy edge-chromium || rpm -q edge-chromium || edge-chromium --version

2. UPGRADE to 151.0.4129.59 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade edge-chromium

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade edge-chromium

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

Exact fixes by distribution

Fedora ELN · selinux-policy · FIXED · 45.23-1.eln159 · FEDORA-2026-3668c969a2 · source

sudo dnf upgrade --advisory=FEDORA-2026-3668c969a2

Fedora 46 · sugar-toolkit-gtk3 · FIXED · 0.122-2.fc46 · FEDORA-2026-d11eb2faf0 · source

sudo dnf upgrade --advisory=FEDORA-2026-d11eb2faf0

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-2026-66311?

edge chromium: upgrade to 151.0.4129.59. Exact commands for each OS are on this page.

Is CVE-2026-66311 being exploited?

CVE-2026-66311 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-2026-66311 affect?

CVE-2026-66311 affects edge chromium. Severity is medium (CVSS 6.2). Missing authorization in Microsoft Edge (Chromium-based) allows an unauthorized attacker to perform tampering locally.

How urgent is CVE-2026-66311?

Priority 35/100. On your watchlist

Software pages

Microsoft Edge vulnerabilities · Chromium vulnerabilities

Related CVEs

CVE-2026-70339 MEDIUM 5.4 UPGRADE Access of resource using incompatible type ('type confusion') in Microsoft Edge (Chromium-based) allows an una
CVE-2026-57990 HIGH 7.4 MITIGATE Files or directories accessible to external parties in Microsoft Edge (Chromium-based) allows an unauthorized
CVE-2026-57989 HIGH 7.4 UPGRADE Origin validation error in Microsoft Edge (Chromium-based) allows an unauthorized attacker to disclose informa
CVE-2026-57978 MEDIUM 5.4 UPGRADE Origin validation error in Microsoft Edge (Chromium-based) allows an unauthorized attacker to perform spoofing
CVE-2026-66321 HIGH 7.4 UPGRADE Access of resource using incompatible type ('type confusion') in Microsoft Edge (Chromium-based) allows an una

References

← Back to latest CVEs