CVE-2020-35111

high
Published — · Modified —
CVSS v3
CVSS v2
VIR risk
8.0

Description

When an extension with the proxy permission registered to receive <all_urls>, the proxy.onRequest callback was not triggered for view-source URLs. While web content cannot navigate to such URLs, a user opening View Source could have inadvertently leaked their IP address. This vulnerability affects Firefox < 84, Thunderbird < 78.6, and Firefox ESR < 78.6.

Predictions

Exploit likelihood
20%
Patch ETA

Heuristic predictions, AS-IS, for prioritization only.

Mitigations

vendor Authored 2026-05-27

Vendor advisory: debian — https://security-tracker.debian.org/tracker/CVE-2020-35111

vendor Authored 2026-05-27

Vendor advisory: suse — https://www.suse.com/security/cve/CVE-2020-35111.html

vendor Authored 2026-05-27

Vendor advisory: arch — https://security.archlinux.org/ASA-202012-25

vendor Authored 2026-05-27

Vendor advisory: arch — https://security.archlinux.org/ASA-202012-23

OS impact

OSVersionStatusFixed in
arch archfixed78.6.0-1
suse slesaffected
debian debiansidfixed84.0-1
debian debianbookwormfixed78.6.0esr-1
debian debianbullseyefixed78.6.0esr-1
debian debianforkyfixed78.6.0esr-1
debian debiantrixiefixed78.6.0esr-1

References

Verify integrity in audit chain (admin only). AS-IS.