CVE-2026-8948: Same-origin policy bypass in the DOM: Networking component
Modified
AliasesUBUNTU-CVE-2026-8948CGA-8226-25x6-v482CGA-97fm-7jpc-gc6q
Published 19-05-2026Last modified 15-07-2026
Vulnerability summary
CVE-2026-8948 is a critical (CVSS 9.1) vulnerability in mozilla firefox. EPSS estimates a 0.45% chance of exploitation in the next 30 days, higher than 38.2% of scored vulnerabilities.
CVSS score
9.1/10
010
Critical · v3.1 (CVE.org)EPSS score
0.45%
0%100%
Low · +0.03 pp in 30 daysKEVNot listedNot listed by any tracked catalog.
RansomwareNot flaggedNo ransomware use recorded.
Public exploits0No public exploits recorded
Advisory lineage
Upstream 0 · Downstream 2 · Related 3Timeline
- 19-05-2026PublishedVulnerability first disclosed.
- 15-07-2026Last modifiedVulnerability information updated.
Description
Same-origin policy bypass in the DOM: Networking component. This vulnerability was fixed in Firefox 151 and Thunderbird 151.
CVSS metrics
3 scores · 3 sources · 1 versionCritical 9.1Preferred score · CVE.org (CNA)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:NSources3 sources · 7.5–9.1
- OSV · UbuntuEcosystem advisory · calculated7.5HighCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:HDiffers
- NVDNIST9.1CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
EPSS trend
Probability
0.45%
Chance of exploitation in the next 30 days
Percentile
38%
Versus all other CVEs
30-day change
Increase +0.03 pp
From 0.42% on 22-09-2026
22-09-202622-10-2026
Known exploited
Compare KEV catalogs
CISA KEVNot in the CISA KEV catalog.
ENISA CNWNot in the ENISA CNW catalog.
CIRCLNot in the CIRCL catalog.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root cause- CWE-942Permissive Cross-domain Security Policy with Untrusted DomainsThe product uses a web-client protection mechanism such as a Content Security Policy (CSP) or cross-domain policy file, but the policy includes untrusted domains with which the web client is allowed to communicate.
- CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.
Affected systems
Ubuntu8 products
- mozjs102All versions (No fix recorded)
- mozjs115All versions (No fix recorded)
- mozjs38All versions (No fix recorded)
- mozjs52All versions (No fix recorded)
- mozjs68All versions (No fix recorded)
Mozilla2 products
- firefox< 151.0.0
- thunderbird< 151.0.0
Chainguard1 product
- firefox< 151-r0
Wolfi1 product
- firefox< 151-r0
4 vendors · 12 products