Sensitive user data could be leaked to other applications through Reader mode

published 2026-05-19 5 mo ago modified 2026-07-23 3 mo ago also EUVD-2026-30943

cvss: 6.5; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.2%; EPSS 0.2% chance of exploitation in 30 days, percentile 8%
public exploits: 0; none known

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.

Patch / fix

fixed in 1

mozilla firefox 151.0

CISA SSVC

Exploitation: none
Automatable: no
Technical impact: partial
Assessed: 5 mo ago (2026-05-19)

Exploit prediction

0.19% chance of exploitation in the next 30 days, higher than 8% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CISA ADP	3.1	6.5	CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
CNA	3.1	6.5	CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

Affected products

Mozilla Firefox for iOS

Classification

Weakness

CWE-306 Missing Authentication for Critical Functionality
CWE-200 Exposure of Sensitive Information to an Unauthorized Actor

References

mozilla.org /security/advisories/mfsa2026-49/
vendor-advisory
bugzilla.mozilla.org /show_bug.cgi?id=2036618
permissions-required

Sources

CVE List CVE-2026-8706
NVD CVE-2026-8706

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.

Summary