Vulnerability · CVE-2025-5266
Script elements loading cross-origin resources generated load and error events which leaked information enabling XS-Leaks attacks.
Published May 27, 2025 · catalog updated Apr 13, 2026 · Script elements loading cross-origin
Check if you run it
No confirmed exploitation is on record for CVE-2025-5266. EPSS is 0.33%. Act only if a listed version of Script elements loading cross-origin is installed.
Gaps on this record
- The stored product name is a package slug. The name on this page is taken from the title (Script elements loading cross-origin).
- No version range is stored. A customer cannot check an installed version against this record.
- No vendor fix or required action is stored. Compare the linked advisory before you change production.
- Severity
- Medium4.3
- Known exploitation
- Not in CISA/VulnCheck KEV
- EPSS
- 0.33%
- Remediation
- Advisory link
- Affected products
- vendor mozilla
Script elements loading cross-origin resources generated load and error events which leaked information enabling XS-Leaks attacks. This vulnerability was fixed in Firefox 139, Firefox ESR 128.11, Thunderbird 139, and Thunderbird 128.11.
Are you affected?
Enter the version you run. The result uses only the ranges stored on this record.
The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.
- vendor mozillaversion unspecified
How to fix CVE-2025-5266
Recommended remediation
A patch or advisory reference is linked. Open the original publisher for availability by product version.
Official advisories
What to do
Three questions, each answered from this record only. Confirm the vendor advisory before you patch.
Should you patch?
No confirmed exploitation is on record for CVE-2025-5266. EPSS is 0.33%. Act only if a listed version of Script elements loading cross-origin is installed.
Which versions are affected?
Affected version ranges are not on this record. Compare the installed version with the linked vendor advisory before you change production.
What should an analyst verify?
No weakness class is stored. EPSS 0.33%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.
Code
The project this record applies to. Exploit listings stay in References.
No public source repository is identified for this product.
Timeline
Detection, updates, and resolution for this record.
May 27, 2025 · EUVD
Detected
Script elements loading cross-origin resources generated load and error events which leaked information enabling XS-Leaks attacks. This vulnerability was fixed in Firefox 139, Firefox ESR 128.11, Thunderbird 139, and Thunderbird 128.11.
Apr 13, 2026 · EUVD
Updated
Script elements loading cross-origin resources generated load and error events which leaked information enabling XS-Leaks attacks. This vulnerability was fixed in Firefox 139, Firefox ESR 128.11, Thunderbird 139, and Thunderbird 128.11.
Sources
- CVE.orgVulnerability recordCVE-2025-5266
Official CVE identifier
cve.org - FIRST EPSSExploitation probabilityCVE-2025-5266
30-day exploitation probability 0.3%
first.org - EUVDVulnerability recordEUVD-2025-18107
Script elements loading cross-origin resources generated load and error events which leaked information enabling XS-Leaks attacks. This vulnerability was fixed in Firefox 139, Firefox ESR 128.11, Thunderbird 139, and Thunderbird 128.11.
euvd.enisa.europa.eu
References
Freshness
Last verified in this catalog Oct 18, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.