CVE-2025-14321VulnerabilityPublished 5 Jan 2026Updated 13 Oct 2026

Red Hat Security Advisory: firefox security update

Affects Red Hat firefoxSource GCVE Database

Mentioned vulnerabilities

Authoritative record:CVE-2025-14321· Critical 9.8

Not known to be exploited · CVSS 9.8 Critical : upgrade the Red Hat redhat/firefox package to 147 or 140.6 as a priority.

Data as of 26 Oct 2026, 09:15 UTC

CVSS 3.1 base score

9.8Critical

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.5% chance of exploitation in 30 days – higher than 48% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 147, 140.6

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Exploitation evidence

Disclosed: evidence found.
CVE published 9 Dec 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade the Red Hat redhat/firefox package to 147 or 140.6.

Affected software

Product	Affected	Fixed in
Red Hatredhat/firefox`pkg:rpm/redhat/firefox`Other threats	Affected >=140.0 <140.6 >=146 <147	Fixed in 140.6 147

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

A security update is available from Red Hat for Firefox and Thunderbird in Red Hat Enterprise Linux 8.6 that addresses these vulnerabilities. Users and administrators should apply the provided updates promptly following Red Hat's official guidance at https://access.redhat.com/articles/11258. No additional mitigations are specified beyond applying the official patches.

Description

Multiple security vulnerabilities affecting Mozilla Firefox and Thunderbird have been identified and fixed in Red Hat Enterprise Linux 8.6. These include memory safety bugs, use-after-free, JIT miscompilation, sandbox escape, privilege escalation, and same-origin policy bypass. The update addresses Firefox ESR 140.6, Thunderbird ESR 140.6, Firefox 146, and Thunderbird 146. Red Hat has released security updates rated as important to remediate these issues.

Impact

The vulnerabilities collectively could allow an attacker to execute arbitrary code, escalate privileges, bypass security policies such as the same-origin policy, or escape sandbox restrictions in affected Firefox and Thunderbird versions. These issues affect both ESR and standard releases of Firefox and Thunderbird as packaged in Red Hat Enterprise Linux 8.6. Successful exploitation could compromise the confidentiality, integrity, and availability of the affected systems.

CWE-94Improper Control of Generation of Code ('Code Injection') (opens in a new tab)
Base weaknessLikelihood of exploit: MediumCWE Top 25 (2025): #10OWASP Top 10 A05:2025: Injection (opens in a new tab)
The product constructs all or part of a code segment using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the syntax or behavior of the intended code segment.
Architecture and Design · Refactoring
Refactor your program so that you do not have to dynamically generate code.
Architecture and Design
Run your code in a "jail" or similar sandbox environment that enforces strict boundaries between the process and the operating system. This may effectively restrict which code can be executed by your product.
Implementation · Input Validation
Assume all input is malicious. Use an "accept known good" input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does.
OWASP Cheat Sheets
Server Side Request Forgery Prevention (opens in a new tab)
Unvalidated Redirects and Forwards (opens in a new tab)
Cross Site Scripting Prevention (opens in a new tab)
DOM based XSS Prevention (opens in a new tab)
Abuse Case (opens in a new tab)
OWASP ASVS 4.0.3
V5.2.8 (opens in a new tab)
V5.2.5 (opens in a new tab)
V1.5.1 (opens in a new tab)
Attack patterns
Leverage Executable Code in Non-Executable Files (opens in a new tab)
Manipulating User-Controlled Variables (opens in a new tab)
Code Injection (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 13 Oct 2026, 22:08 UTC

WeaknessesCWE-94

Technical details

References

Community reviews

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