CVE-2026-15719: We are aware that exploit code for this is public however we are not aware of any attacks in the wild abusing

Q: How do I fix CVE-2026-15719?

firefox: upgrade to 152.0.6. Exact commands for each OS are on this page.

Q: Is CVE-2026-15719 being exploited?

CVE-2026-15719 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-2026-15719 affect?

CVE-2026-15719 affects firefox. Severity is medium (CVSS 5.4). We are aware that exploit code for this is public however we are not aware of any attacks in the wild abusing this flaw. This vulnerability was fixed in Firefox 152.0.6, Firefox ESR 115.38, Firefox ESR 140.13, and Thunderbird 140.13.

Q: How urgent is CVE-2026-15719?

Priority 24/100. No elevated risk signals yet.

Routine

MEDIUM 5.4UPGRADE

CVE-2026-15719 is a medium-severity flaw (CVSS 5.4) affecting firefox. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

We are aware that exploit code for this is public however we are not aware of any attacks in the wild abusing this flaw. This vulnerability was fixed in Firefox 152.0.6, Firefox ESR 115.38, Firefox ESR 140.13, and Thunderbird 140.13.

Why this priority

No elevated risk signals yet

A fixed release or distro patch exists.

Risk facts

CVSS score	5.4 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	Required
EPSS exploit chance	0.3% (top 79%)
CISA exploited list	No
Published	2026-07-14
Last modified	2026-07-22

Publisher (CNA): Mozilla Corporation · Vendor: mozilla

Last updated 2026-07-22 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-07-14 13:18 UTCPublished CVE record published
2026-07-22 20:16 UTCUpdated Record last modified

mozilla firefox UPGRADE

Affected: < 152.0.6

Fixed in: 152.0.6

Safe to downgrade to: no unaffected older release

1. Check installed version

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

2. UPGRADE to 152.0.6 (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.

Advisories and coverage

Official advisories

AlmaLinux Errata: [ALSA-2026:49921] Important: thunderbird security update 2026-08-06

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-2026-15719?

firefox: upgrade to 152.0.6. Exact commands for each OS are on this page.

Is CVE-2026-15719 being exploited?

CVE-2026-15719 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-2026-15719 affect?

CVE-2026-15719 affects firefox. Severity is medium (CVSS 5.4). We are aware that exploit code for this is public however we are not aware of any attacks in the wild abusing this flaw. This vulnerability was fixed in Firefox 152.0.6, Firefox ESR 115.38, Firefox ESR 140.13, and Thunderbird 140.13.

How urgent is CVE-2026-15719?

Priority 24/100. No elevated risk signals yet.

Software pages

Mozilla Firefox vulnerabilities · Mozilla Thunderbird vulnerabilities

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References

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