How severe is CVE-2021-3778?

CVE-2021-3778 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-2021-3778 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (73rd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-3778?

CVE-2021-3778 primarily affects Vim. In total, 6 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2021-3778?

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-2021-3778 published?

CVE-2021-3778 was published on 2021-09-15 and last updated on 2026-06-17.

CVE-2021-3778

CVE-2021-3778 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-122.

Key facts

Severity: High (CVSS 3.x base score 7.8)
CVSS v2: 6.8
EPSS exploit prediction: 2% (73rd percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-122
Affected product: Vim
Published: 2021-09-15
Last modified: 2026-06-17

Description

vim is vulnerable to Heap-based Buffer Overflow

Frequently asked questions

What is CVE-2021-3778?: vim is vulnerable to Heap-based Buffer Overflow
How severe is CVE-2021-3778?: CVE-2021-3778 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-2021-3778 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (73rd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-3778?: CVE-2021-3778 primarily affects Vim. In total, 6 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-3778?: 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-2021-3778 published?: CVE-2021-3778 was published on 2021-09-15 and last updated on 2026-06-17.

References

Affected products (6)

cpe:2.3:a:vim:vim:*:*:*:*:*:*:*:*
cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:*
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:a:netapp:ontap_select_deploy_administration_utility:-:*:*:*:*:*:*:*

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…
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