CVE-2026-6775: Incorrect boundary conditions in the WebRTC component

Q: How do I fix CVE-2026-6775?

firefox: upgrade to 150.0; thunderbird: upgrade to 150.0. Exact commands for each OS are on this page.

Q: Is CVE-2026-6775 being exploited?

CVE-2026-6775 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-2026-6775 affect?

CVE-2026-6775 affects firefox, thunderbird. Severity is medium (CVSS 5.3). Incorrect boundary conditions in the WebRTC component. This vulnerability was fixed in Firefox 150 and Thunderbird 150.

Q: How urgent is CVE-2026-6775?

Priority 26/100. Remotely exploitable, no login, no user action

Routine

MEDIUM 5.3REMOTEUPGRADEUPGRADE

CVE-2026-6775 is a medium-severity flaw (CVSS 5.3) affecting firefox, thunderbird. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Incorrect boundary conditions in the WebRTC component. This vulnerability was fixed in Firefox 150 and Thunderbird 150.

Why this priority

Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	5.3 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.2% (top 89%)
CISA exploited list	No
Weakness	CWE-119
Published	2026-04-21
Last modified	2026-10-26

Publisher (CNA): Mozilla Corporation · Vendor: mozilla

Last updated 2026-10-26 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-04-21 13:16 UTCPublished CVE record published
2026-10-26 21:10 UTCUpdated Record last modified

mozilla firefox UPGRADE

Affected: < 150.0

Fixed in: 150.0

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy firefox || rpm -q firefox || firefox --version

2. UPGRADE to 150.0 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade firefox

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade firefox

Note

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

mozilla thunderbird UPGRADE

Affected: < 150.0

Fixed in: 150.0

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy thunderbird || rpm -q thunderbird || thunderbird --version

2. UPGRADE to 150.0 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade thunderbird

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade thunderbird

Note

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

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-2026-6775?

firefox: upgrade to 150.0; thunderbird: upgrade to 150.0. Exact commands for each OS are on this page.

Is CVE-2026-6775 being exploited?

CVE-2026-6775 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-2026-6775 affect?

CVE-2026-6775 affects firefox, thunderbird. Severity is medium (CVSS 5.3). Incorrect boundary conditions in the WebRTC component. This vulnerability was fixed in Firefox 150 and Thunderbird 150.

How urgent is CVE-2026-6775?

Priority 26/100. Remotely exploitable, no login, no user action

Software pages

Mozilla Firefox vulnerabilities · Mozilla Thunderbird vulnerabilities

Related CVEs

CVE-2026-100801 HIGH 8.8 UPGRADE UPGRADE Privilege escalation in the DLL Services component
CVE-2026-6746 HIGH 7.5 UPGRADE UPGRADE Use-after-free in the DOM: Core & HTML component
CVE-2026-6758 HIGH 7.5 UPGRADE UPGRADE Use-after-free in the JavaScript: WebAssembly component
CVE-2026-6771 CRITICAL 9.8 UPGRADE UPGRADE Mitigation bypass in the DOM: Security component
CVE-2026-6747 HIGH 7.5 UPGRADE UPGRADE Use-after-free in the WebRTC component

References

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