How severe is CVE-2019-11745?

CVE-2019-11745 has a CVSS 3.x base score of 8.8, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2019-11745 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 3% (86th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2019-11745?

CVE-2019-11745 primarily affects Mozilla Firefox. In total, 17 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2019-11745?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2019-11745 published?

CVE-2019-11745 was published on 2020-01-08 and last updated on 2026-06-17.

CVE-2019-11745

CVE-2019-11745 is a high-severity vulnerability in Mozilla Firefox with a CVSS 3.x base score of 8.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-787.

Key facts

Severity: High (CVSS 3.x base score 8.8)
CVSS v2: 6.8
EPSS exploit prediction: 3% (86th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-787
Affected product: Mozilla Firefox
Published: 2020-01-08
Last modified: 2026-06-17

Description

When encrypting with a block cipher, if a call to NSC_EncryptUpdate was made with data smaller than the block size, a small out of bounds write could occur. This could have caused heap corruption and a potentially exploitable crash. This vulnerability affects Thunderbird < 68.3, Firefox ESR < 68.3, and Firefox < 71.

Frequently asked questions

What is CVE-2019-11745?: When encrypting with a block cipher, if a call to NSC_EncryptUpdate was made with data smaller than the block size, a small out of bounds write could occur. This could have caused heap corruption and a potentially exploitable crash. This vulnerability affects Thunderbird < 68.3, Firefox ESR < 68.3, and Firefox < 71.
How severe is CVE-2019-11745?: CVE-2019-11745 has a CVSS 3.x base score of 8.8, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2019-11745 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 3% (86th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2019-11745?: CVE-2019-11745 primarily affects Mozilla Firefox. In total, 17 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2019-11745?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2019-11745 published?: CVE-2019-11745 was published on 2020-01-08 and last updated on 2026-06-17.

References

Affected products (17)

cpe:2.3:a:mozilla:firefox:*:*:*:*:*:*:*:*
cpe:2.3:a:mozilla:firefox_esr:*:*:*:*:*:*:*:*
cpe:2.3:a:mozilla:thunderbird:*:*:*:*:*:*:*:*
cpe:2.3:o:opensuse:leap:15.1:*:*:*:*:*:*:*
cpe:2.3:o:canonical:ubuntu_linux:16.04:*:*:*:lts:*:*:*
cpe:2.3:o:canonical:ubuntu_linux:18.04:*:*:*:lts:*:*:*
cpe:2.3:o:canonical:ubuntu_linux:19.10:*:*:*:*:*:*:*
cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux_server_aus:6.6:*:*:*:*:*:*:*
cpe:2.3:o:siemens:ruggedcom_rox_mx5000_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:siemens:ruggedcom_rox_rx1400_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:siemens:ruggedcom_rox_rx1500_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:siemens:ruggedcom_rox_rx1501_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:siemens:ruggedcom_rox_rx1510_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:siemens:ruggedcom_rox_rx1511_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:siemens:ruggedcom_rox_rx1512_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:siemens:ruggedcom_rox_rx5000_firmware:*:*:*:*:*:*:*:*

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