CVE-2026-8706: Sensitive user data could be leaked to other applications through Reader mode
Vulnerability summary
CVE-2026-8706 is a medium (CVSS 6.5) vulnerability in mozilla firefox. EPSS estimates a 0.19% chance of exploitation in the next 30 days, higher than 8.9% of scored vulnerabilities.
Not severe (CVSS 6.5, adjacent network); no exploitation reported by the 5 checked sources
Source freshness unavailable
How is this decided?Advisory lineage
Upstream 0 · Downstream 0 · Related 1Timeline
- 19-05-2026PublishedVulnerability first disclosed.
- 19-05-2026Last modifiedVulnerability information updated.
Description
Firefox for iOS hosted Reader mode on an unauthenticated local web server, allowing another application on the same device to request arbitrary URLs and receive the response rendered with the signed-in user's cookies. This vulnerability was fixed in Firefox for iOS 151.0.
CVSS metrics
3 scores · 3 sources · 1 version- OSV · UbuntuEcosystem advisory · calculated6.5MediumCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
- NVDNIST6.5MediumCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
EPSS trend
Probability
0.19%
Chance of exploitation in the next 30 days
Percentile
9%
Versus all other CVEs
30-day change
Decrease -0.04 pp
From 0.23% on 04-10-2026
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-200Exposure of Sensitive Information to an Unauthorized ActorThe product exposes sensitive information to an actor that is not explicitly authorized to have access to that information.
- CWE-306Missing Authentication for Critical FunctionalityThe product does not perform any authentication for functionality that requires a provable user identity or consumes a significant amount of resources.
Affected systems
Known conditions: adjacent network, no authentication, no user interaction (CVSS vector). Other conditions: not stated in public data.
Ubuntu6 products
- mozjs102All versions (No fix recorded)
- mozjs115All versions (No fix recorded)
- mozjs52All versions (No fix recorded)
- mozjs68All versions (No fix recorded)
- mozjs78All versions (No fix recorded)
Chainguard1 product
- firefox< 151.0-r0
Mozilla1 product
- firefox< 151.0
Wolfi1 product
- firefox< 151.0-r0
4 vendors · 9 products