Red Hat Security Advisory: firefox security update
Affects Red HatSource GCVE Database
Mentioned vulnerabilities
Not known to be exploited.
Data as of 25 Oct 2026, 19:02 UTC
Rated by Threat Radar · No CVSS score from NVD or the CNA
- EPSS
- 9.5% chance of exploitation in 30 days – higher than 95% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Exploitation evidence
Disclosed: evidence found.
CVE published 9 Jun 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 2026-10-25.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| Red Hat Product Security Red Hat | Affected
| Fixed in– |
AI-suggested
Red Hat has released updated Firefox packages for Red Hat Enterprise Linux 8.6 to address these vulnerabilities. Users should apply the official security update as described in Red Hat advisory RHSA-2025:8645. For detailed update instructions, refer to https://access.redhat.com/articles/11258. No additional mitigation steps are indicated by the vendor.
Description
Two security vulnerabilities (CVE-2025-4918 and CVE-2025-4919) affecting Mozilla Firefox and Thunderbird were addressed by Red Hat in an important security update for Red Hat Enterprise Linux 8.6. Both issues involve out-of-bounds access errors related to Promise object resolution and linear sum optimization. Red Hat has released updated Firefox packages to remediate these vulnerabilities.
References
- access.redhat.com/errata/RHSA-2025:8645 (opens in a new tab)
- access.redhat.com/security/updates/classification/ (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2367016 (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2367018 (opens in a new tab)
- security.access.redhat.com/data/csaf/v2/advisories/2025/rhsa-2025_8645.json (opens in a new tab)