CVE-2019-11759
An attacker could have caused 4 bytes of HMAC output to be written past the end of a buffer stored on the stack.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (1.65%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
Description
An attacker could have caused 4 bytes of HMAC output to be written past the end of a buffer stored on the stack. This could be used by an attacker to execute arbitrary code or more likely lead to a crash. This vulnerability affects Firefox < 70, Thunderbird < 68.2, and Firefox ESR < 68.2.
- CVSS 3.1
- 8.8 HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
- EPSS
- 1.65% probability · 76th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Weakness
- CWE-120
- Affected
- mozilla/firefox · mozilla/firefox esr · mozilla/thunderbird · canonical/ubuntu linux
- Source
- security@mozilla.org
EPSS 1.6% since 27 October 2026; no change recorded yet. Points are recorded when the score first appears and whenever it moves by a percentage point or more.
References
- https://bugzilla.mozilla.org/show_bug.cgi?id=1577953Issue Tracking, Permissions Required
- https://security.gentoo.org/glsa/202003-10Third Party Advisory
- https://usn.ubuntu.com/4335-1/Third Party Advisory
- https://www.mozilla.org/security/advisories/mfsa2019-33/Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2019-34/Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2019-35/Vendor Advisory
- https://bugzilla.mozilla.org/show_bug.cgi?id=1577953Issue Tracking, Permissions Required
- https://security.gentoo.org/glsa/202003-10Third Party Advisory
- https://usn.ubuntu.com/4335-1/Third Party Advisory
- https://www.mozilla.org/security/advisories/mfsa2019-33/Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2019-34/Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2019-35/Vendor Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.