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CVE-2021-43541
When invoking protocol handlers for external protocols, a supplied parameter URL containing spaces was not properly escaped. This…
Medium6.5EPSS 1.7%
- Published
- Updated
- Reserved
- Assigned by
- mozilla
Description
When invoking protocol handlers for external protocols, a supplied parameter URL containing spaces was not properly escaped. This vulnerability affects Thunderbird < 91.4.0, Firefox ESR < 91.4.0, and Firefox < 95.
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:N/I:H/A:N |
- EPSS (exploitation in 30 days)
- 1.7% · top 23% of all CVEs (6 Nov 2026)
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The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 6.5.
Weakness
- External protocol handler parameters were unescaped
Affected products
- affected unspecified – < 91.4.0
- affected unspecified – < 91.4.0
- affected unspecified – < 95
References (10)
- https://www.mozilla.org/security/advisories/mfsa2021-53/ (opens in a new tab)x_refsource_MISCx_transferred
- https://www.mozilla.org/security/advisories/mfsa2021-54/ (opens in a new tab)x_refsource_MISCx_transferred
- https://www.mozilla.org/security/advisories/mfsa2021-52/ (opens in a new tab)x_refsource_MISCx_transferred
- https://bugzilla.mozilla.org/show_bug.cgi?id=1696685 (opens in a new tab)x_refsource_MISCx_transferred
- DSA-5026 (opens in a new tab)vendor-advisoryx_refsource_DEBIANx_transferred
- [debian-lts-announce] 20211229 [SECURITY] [DLA 2863-1] firefox-esr security update (opens in a new tab)mailing-listx_refsource_MLISTx_transferred
- DSA-5034 (opens in a new tab)vendor-advisoryx_refsource_DEBIANx_transferred
- [debian-lts-announce] 20220104 [SECURITY] [DLA 2874-1] thunderbird security update (opens in a new tab)mailing-listx_refsource_MLISTx_transferred
- GLSA-202202-03 (opens in a new tab)vendor-advisoryx_refsource_GENTOOx_transferred
- GLSA-202208-14 (opens in a new tab)vendor-advisoryx_refsource_GENTOOx_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)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
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[](https://trackcve.app/cve/CVE-2021-43541)Record last updated .