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CVE-2019-11763

MEDIUM
6.1
CVSS Score
Published: January 8, 2020 at 07:59 PM UTC
Updated: June 17, 2026 at 02:13 AM UTC
4 products affected across 2 vendorsUbuntu LinuxFirefoxThunderbird

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Severity
MEDIUM6.1
Exploit prediction
EPSS 1%

Description

Failure to correctly handle null bytes when processing HTML entities resulted in Firefox incorrectly parsing these entities. This could have led to HTML comment text being treated as HTML which could have led to XSS in a web application under certain conditions. It could have also led to HTML entities being masked from filters - enabling the use of entities to mask the actual characters of interest from filters. This vulnerability affects Firefox < 70, Thunderbird < 68.2, and Firefox ESR < 68.2.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

Ubuntu Linux· Canonicalrubygems
95%
16.04
Firefox· Mozilla
95%
v < 70v < 70.0
Affected range stops below 70, so it looks safe — our inference, not a vendor statement
Affected range stops below 70.0, so it looks safe — our inference, not a vendor statement
Firefox ESR· Mozilla
95%
v < 68.2
Affected range stops below 68.2, so it looks safe — our inference, not a vendor statement
Thunderbird· Mozilla
95%
v < 68.2
Affected range stops below 68.2, so it looks safe — our inference, not a vendor statement

References (6)

x_refsource_CONFIRMIssue TrackingPermissions Required
Source: [email protected]
https://bugzilla.mozilla.org/show_bug.cgi?id=1584216
Vendor Advisoryx_refsource_GENTOOThird Party Advisory
Source: [email protected]
https://security.gentoo.org/glsa/202003-10
Vendor Advisoryx_refsource_UBUNTUThird Party Advisory
Source: [email protected]
https://usn.ubuntu.com/4335-1/
x_refsource_CONFIRMVendor Advisory
Source: [email protected]
https://www.mozilla.org/security/advisories/mfsa2019-33/
x_refsource_CONFIRMVendor Advisory
Source: [email protected]
https://www.mozilla.org/security/advisories/mfsa2019-34/
x_refsource_CONFIRMVendor Advisory
Source: [email protected]
https://www.mozilla.org/security/advisories/mfsa2019-35/

CVSS

6.1MEDIUM[email protected]
Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
REQUIRED
Scope
CHANGED
Confidentiality
LOW
Integrity
LOW
Availability
NONE
Vector?

Quick Info

StatusMODIFIED
CWE
CWE-79

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