How severe is CVE-2020-12267?

CVE-2020-12267 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2020-12267 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (82nd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2020-12267?

CVE-2020-12267 affects Qt. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2020-12267?

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

When was CVE-2020-12267 published?

CVE-2020-12267 was published on 2020-04-27 and last updated on 2026-06-17.

CVE-2020-12267

CVE-2020-12267 is a critical-severity vulnerability in Qt with a CVSS 3.x base score of 9.8. 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-416.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v2: 7.5
EPSS exploit prediction: 2% (82nd percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-416
Affected product: Qt
Published: 2020-04-27
Last modified: 2026-06-17

Description

setMarkdown in Qt before 5.14.2 has a use-after-free related to QTextMarkdownImporter::insertBlock.

Frequently asked questions

What is CVE-2020-12267?: setMarkdown in Qt before 5.14.2 has a use-after-free related to QTextMarkdownImporter::insertBlock.
How severe is CVE-2020-12267?: CVE-2020-12267 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2020-12267 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (82nd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2020-12267?: CVE-2020-12267 affects Qt. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2020-12267?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2020-12267 published?: CVE-2020-12267 was published on 2020-04-27 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:qt:qt:5.14.1:*:*:*:*:*:*:*

More vulnerabilities in Qt

CVE-2024-36048 — Critical (CVSS 9.8): QAbstractOAuth in Qt Network Authorization in Qt before 5.15.17, 6.x before 6.2.13, 6.3.x through 6.5.x before 6.5.6,…
CVE-2023-51714 — Critical (CVSS 9.8): An issue was discovered in the HTTP2 implementation in Qt before 5.15.17, 6.x before 6.2.11, 6.3.x through 6.5.x before…
CVE-2018-19873 — Critical (CVSS 9.8): An issue was discovered in Qt before 5.11.3. QBmpHandler has a buffer overflow via BMP data.
CVE-2017-10904 — Critical (CVSS 9.8): Qt for Android prior to 5.9.0 allows remote attackers to execute arbitrary OS commands via unspecified vectors.
CVE-2011-3194 — Critical (CVSS 9.3): Buffer overflow in the TIFF reader in gui/image/qtiffhandler.cpp in Qt 4.7.4 allows remote attackers to cause a denial…
CVE-2011-3193 — Critical (CVSS 9.3): Heap-based buffer overflow in the Lookup_MarkMarkPos function in the HarfBuzz module (harfbuzz-gpos.c), as used by Qt…

All CVEs affecting Qt →

Other CWE-416 (Use After Free) vulnerabilities

CVE-2026-13782 — Critical (CVSS 10.0): Use after free in Browser in Google Chrome prior to 150.0.7871.47 allowed a remote attacker who had compromised the…
CVE-2026-4725 — Critical (CVSS 10.0): Sandbox escape due to use-after-free in the Graphics: Canvas2D component. This vulnerability was fixed in Firefox 149…
CVE-2026-4688 — Critical (CVSS 10.0): Sandbox escape due to use-after-free in the Disability Access APIs component. This vulnerability was fixed in Firefox…
CVE-2025-24085 — Critical (CVSS 10.0): A use after free issue was addressed with improved memory management. This issue is fixed in iOS 18.3 and iPadOS 18.3,…
CVE-2024-43102 — Critical (CVSS 10.0): Concurrent removals of certain anonymous shared memory mappings by using the UMTX_SHM_DESTROY sub-request of…
CVE-2021-32495 — Critical (CVSS 10.0): Radare2 has a use-after-free vulnerability in pyc parser's get_none_object function. Attacker can read freed memory…

Browse all CWE-416 (Use After Free) vulnerabilities →