How severe is CVE-2021-3974?

CVE-2021-3974 has a CVSS 3.x base score of 7.8, rated high severity. It is exploitable over local access with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2021-3974 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (66th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-3974?

CVE-2021-3974 primarily affects Vim. In total, 5 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2021-3974?

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-2021-3974 published?

CVE-2021-3974 was published on 2021-11-19 and last updated on 2026-06-17.

CVE-2021-3974

CVE-2021-3974 is a high-severity vulnerability in Vim with a CVSS 3.x base score of 7.8. 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: High (CVSS 3.x base score 7.8)
CVSS v2: 6.8
EPSS exploit prediction: 1% (66th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-416
Affected product: Vim
Published: 2021-11-19
Last modified: 2026-06-17

Description

vim is vulnerable to Use After Free

Frequently asked questions

What is CVE-2021-3974?: vim is vulnerable to Use After Free
How severe is CVE-2021-3974?: CVE-2021-3974 has a CVSS 3.x base score of 7.8, rated high severity. It is exploitable over local access with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2021-3974 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (66th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-3974?: CVE-2021-3974 primarily affects Vim. In total, 5 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-3974?: 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-2021-3974 published?: CVE-2021-3974 was published on 2021-11-19 and last updated on 2026-06-17.

References

Affected products (5)

cpe:2.3:a:vim:vim:*:*:*:*:*:*:*:*
cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:*
cpe:2.3:o:fedoraproject:fedora:35:*:*:*:*:*:*:*
cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*
cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:*

More vulnerabilities in Vim

CVE-2020-20703 — Critical (CVSS 9.8): Buffer Overflow vulnerability in VIM v.8.1.2135 allows a remote attacker to execute arbitrary code via the operand…
CVE-2022-3520 — Critical (CVSS 9.8): Heap-based Buffer Overflow in GitHub repository vim/vim prior to 9.0.0765.
CVE-2022-0318 — Critical (CVSS 9.8): Heap-based Buffer Overflow in vim/vim prior to 8.2.
CVE-2017-6350 — Critical (CVSS 9.8): An integer overflow at an unserialize_uep memory allocation site would occur for vim before patch 8.0.0378, if it does…
CVE-2017-6349 — Critical (CVSS 9.8): An integer overflow at a u_read_undo memory allocation site would occur for vim before patch 8.0.0377, if it does not…
CVE-2017-5953 — Critical (CVSS 9.8): vim before patch 8.0.0322 does not properly validate values for tree length when handling a spell file, which may…

All CVEs affecting Vim →

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 →