CVE-2021-23985If an attacker is able to alter specific about:config values (for example malware running on the user's computer), the Devtools remote…
- 6.5MediumCVSS base score
- 1.5%Exploitation in 30 daysEPSS · top 25% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- NonePublic exploitsnone known yet
Description
If an attacker is able to alter specific about:config values (for example malware running on the user's computer), the Devtools remote debugging feature could have been enabled in a way that was unnoticable to the user. This would have allowed a remote attacker (able to make a direct network connection to the victim) to monitor the user's browsing activity and (plaintext) network traffic. This was addressed by providing a visual cue when Devtools has an open network socket. This vulnerability affects Firefox < 87.
Timeline
ID reserved
By mozilla
- 3 months later
· 3 months later
Published
- 3 years later
· 3 years later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| NVDNVD · Modified | 3.1 | Medium6.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N |
- EPSS (exploitation in 30 days)
- 1.5% · top 25% of all CVEs (12 Nov 2026)
The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 6.5.
Affected products
References
References2
- https://www.mozilla.org/security/advisories/mfsa2021-10/ (opens in a new tab)x_refsource_MISCx_transferred
- https://bugzilla.mozilla.org/show_bug.cgi?id=1659129 (opens in a new tab)x_refsource_MISCx_transferred
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2021-10905 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2021-23985)Record last updated .