CVE-2025-8027: Mozilla Firefox · Vulnerability
Affects Mozilla FirefoxSource CVE Database V5
Not known to be exploited · CVSS 6.5 Medium : upgrade to 141 when convenient.
Data as of 25 Oct 2026, 19:02 UTC
- EPSS
- 0.4% chance of exploitation in 30 days – higher than 37% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 141
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:NExploitation evidence
Disclosed: evidence found.
CVE published 22 Jul 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
Upgrade Mozilla Firefox to 141.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| Mozilla Firefox | Affected
| Fixed in
|
AI-suggested
Mozilla has released official fixes for this vulnerability in Firefox 141, Firefox ESR 115.26, Firefox ESR 128.13, Firefox ESR 140.1, Thunderbird 141, Thunderbird 128.13, and Thunderbird 140.1. Users and administrators should update to these versions or later to remediate the issue. Since this is not a cloud service, patching the client software is required. Patch status is confirmed by Mozilla advisories MFSA 2025-56 and MFSA 2025-57.
Description
On 64-bit platforms IonMonkey-JIT only wrote 32 bits of the 64-bit return value space on the stack. Baseline-JIT, however, read the entire 64 bits. This vulnerability was fixed in Firefox 141, Firefox ESR 115.26, Firefox ESR 128.13, Firefox ESR 140.1, Thunderbird 141, Thunderbird 128.13, and Thunderbird 140.1.
References
- bugzilla.mozilla.org/show_bug.cgi?id=1968423 (opens in a new tab)
- mozilla.org/security/advisories/mfsa2025-56/ (opens in a new tab)
- mozilla.org/security/advisories/mfsa2025-57/ (opens in a new tab)
- mozilla.org/security/advisories/mfsa2025-58/ (opens in a new tab)
- mozilla.org/security/advisories/mfsa2025-59/ (opens in a new tab)
- mozilla.org/security/advisories/mfsa2025-61/ (opens in a new tab)
- mozilla.org/security/advisories/mfsa2025-62/ (opens in a new tab)
- mozilla.org/security/advisories/mfsa2025-63/ (opens in a new tab)
- lists.debian.org/debian-lts-announce/2025/07/msg00016.html (opens in a new tab)