CVE-2026-14241: Memory safety bugs present in Firefox 152.0.3

This month

CRITICAL 9.8REMOTEDOWNGRADE

CVE-2026-14241 is a critical-severity flaw (CVSS 9.8) affecting firefox. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Memory safety bugs present in Firefox 152.0.3. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability was fixed in Firefox 152.0.4.

Why this priority

Critical severity
Remotely exploitable, no login, no user action

No fix is published yet: follow the downgrade or mitigation steps.

Risk facts

CVSS score	9.8 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.4% (top 63%)
CISA exploited list	No
Weakness	CWE-787, CWE-119
Published	2026-06-30
Last modified	2026-10-25

Publisher (CNA): Mozilla Corporation · Vendor: mozilla

Last updated 2026-10-25 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-06-30 14:16 UTCPublished CVE record published
2026-10-25 21:10 UTCUpdated Record last modified

mozilla firefox DOWNGRADE

Affected: 152.0.3

Fixed in: no fixed release known

Safe to downgrade to: a release before 152.0.3

1. Check installed version

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

2. No fixed release: DOWNGRADE to a release before 152.0.3 (Debian / Ubuntu)

apt-cache madison firefox sudo apt install firefox=<VERSION_BEFORE_152.0.3> sudo apt-mark hold firefox

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list firefox sudo dnf downgrade firefox-<VERSION_BEFORE_152.0.3> sudo dnf versionlock add firefox

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

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-2026-14241?

firefox: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2026-14241 being exploited?

CVE-2026-14241 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-2026-14241 affect?

CVE-2026-14241 affects firefox. Severity is critical (CVSS 9.8). Memory safety bugs present in Firefox 152.0.3. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability was fixed in Fir

How urgent is CVE-2026-14241?

Priority 49/100. Critical severity; Remotely exploitable, no login, no user action

Software pages

Mozilla Firefox vulnerabilities

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References

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