CVE-2021-29958 json
When a download was initiated, the client did not check whether it was in normal or private browsing mode, which led to private mode cookie…
published 2021-06-24 5 y ago modified 2026-06-17 4 mo ago also EUVD-2021-16417
- cvss
- 4.3
- version 3.1, NVD
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.7%
- EPSS 0.7% chance of exploitation in 30 days, percentile 52%
- public exploits
- 0
- none known
Summary
When a download was initiated, the client did not check whether it was in normal or private browsing mode, which led to private mode cookies being shared in normal browsing mode. This vulnerability affects Firefox for iOS < 34.
Patch / fix
- Mozilla Firefox for iOS 34
Exploit prediction
0.67% chance of exploitation in the next 30 days, higher than 52% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| NVD | 3.1 | 4.3 | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N |
| NVD | 2.0 | 4.3 | AV:N/AC:M/Au:N/C:P/I:N/A:N |
Affected products
- Mozilla Firefox for iOS
Classification
- Weakness
-
- CWE-862 Missing Authorization
References
-
mozilla.org
/security/advisories/mfsa2021-25/
release-notes, vendor-advisory
-
bugzilla.mozilla.org
/show_bug.cgi?id=1670127
permissions-required, vendor-advisory
Sources
- CVE List CVE-2021-29958
- NVD CVE-2021-29958
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