CVE-2021-3778 | Heap-based Buffer Overflow in vim/vim

Exp

vim is vulnerable to Heap-based Buffer Overflow

Published: 2021-09-15 Last update: 2026-06-17 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2021-3778 is rated High Exploit Risk (72.6/100): CVSS High severity, with medium exploitation likelihood (EPSS 1.74%). 1 public exploit reference(s) are indexed (Exploit-DB). Public exploits are available—assess exposure, apply mitigations, and prioritize patching.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Public exploit references (Exploit-DB) for CVE-2021-3778

EDB-ID Source Kind Published Link
— nvd_ref exploit_tag Exploit-DB ↗

Exploit prediction scoring system (EPSS) score for CVE-2021-3778

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-07-09 1.61% 1.74% +0.12%
2 2026-06-15 0.39% 1.61% +1.22%
3 2025-11-21 — 0.39% —

Full EPSS history (23 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2021-3778

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.8 3.1 HIGH
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H Click to expand
Attack vector (AV:L)
They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:R)
A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 1.8 5.9 [email protected]
7.8 3.0 HIGH
CVSS:3.0/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H Click to expand
Attack vector (AV:L)
They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:R)
A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 1.8 5.9 [email protected]
6.8 2.0 MEDIUM
AV:N/AC:M/Au:N/C:P/I:P/A:P Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:M)
Exploitation needs some favorable conditions, but not exceptional ones.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:P)
Partial confidentiality impact.
Integrity impact (I:P)
Partial integrity impact.
Availability impact (A:P)
Partial availability impact.
 8.6 6.4 [email protected]

Weakness enumeration for CVE-2021-3778

OS Trackers for CVE-2021-3778

vendor priority summary link
alpine high CVE-2021-3778: 2 source package rows (gvim, vim); 30 state rows across 10 repos (3.11-main, 3.12-main, 3.17-main, 3.18-main, 3.19-main, 3.20-main, 3.21-main, 3.22-main, edge-community, edge-main); fixed 10, open 20. https://security.alpinelinux.org/vuln/CVE-2021-3778
debian not yet assigned CVE-2021-3778 not yet assigned priority: Debian including 1 source packages (vim), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2021-3778
gentoo low CVE-2021-3778: 1 GLSA(s) (202208-32), 3 atom(s) (app-editors/gvim, app-editors/vim, app-editors/vim-core); latest impact low. https://bugs.gentoo.org/buglist.cgi?quicksearch=CVE-2021-3778
redhat medium — https://access.redhat.com/security/cve/CVE-2021-3778
suse medium CVE-2021-3778 severity moderate: SUSE including 289 source package names (0.49.0.18.8:vim-8.0.1568-5.17.1, 0.49.0.18.8:vim-data-common-8.0.1568-5.17.1, …), 725 product×package rows across 207 product lines (Container ses/7.1/ceph/haproxy, Container suse/sle-micro-rancher/5.2, … (207 product lines)): Fixed 536, Known Affected 178, Known Not Affected 11. https://www.suse.com/security/cve/CVE-2021-3778/
ubuntu medium CVE-2021-3778 medium priority: Ubuntu including 1 source packages (vim), 8 status rows across 8 suites (bionic, focal, hirsute, impish, jammy, trusty, upstream, xenial): released 8. https://ubuntu.com/security/CVE-2021-3778

Affected software / configurations for CVE-2021-3778

Vendor Product Version Raw CPE
vim vim < 8.2.3409 cpe:2.3:a:vim:vim:*:*:*:*:*:*:*:*
fedoraproject fedora 33 cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:*
fedoraproject fedora 34 cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:*
fedoraproject fedora 35 cpe:2.3:o:fedoraproject:fedora:35:*:*:*:*:*:*:*
debian debian_linux 9.0 cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*
netapp ontap_select_deploy_administration_utility — cpe:2.3:a:netapp:ontap_select_deploy_administration_utility:-:*:*:*:*:*:*:*

References for CVE-2021-3778

URL Tags
http://www.openwall.com/lists/oss-security/2021/10/01/1 Mailing List
https://github.com/vim/vim/commit/65b605665997fad54ef39a93199e305af2fe4d7f Patch Third Party Advisory
https://huntr.dev/bounties/d9c17308-2c99-4f9f-a706-f7f72c24c273 Exploit Issue Tracking Patch Third Party Advisory
https://lists.debian.org/debian-lts-announce/2022/01/msg00003.html Mailing List Third Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/7K4JJBIH3OQSZRVTWKCJCDLGMFGQ5DOH/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/S42L4Z4DTW4LHLQ4FJ33VEOXRCBE7WN4/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/TE62UMYBZE4AE53K6OBBWK32XQ7544QM/
https://security.gentoo.org/glsa/202208-32 Third Party Advisory
https://security.netapp.com/advisory/ntap-20221118-0003/ Third Party Advisory
cvelogic Threat Intelligence