CVE-2021-3770 | Heap-based Buffer Overflow in vim/vim

Exp

vim is vulnerable to Heap-based Buffer Overflow

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

CVE-2021-3770 is rated High Exploit Risk (63.6/100): CVSS High severity, with low exploitation likelihood (EPSS 0.71%). 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-2021-3770

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

Exploit prediction scoring system (EPSS) score for CVE-2021-3770

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 2026-06-15 0.29% 0.71% +0.42%
2 2025-12-25 0.15% 0.29% +0.14%
3 2025-12-08 — 0.15% —

Full EPSS history (19 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2021-3770

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:L/UI:N/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:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
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]
8.6 3.0 HIGH
CVSS:3.0/AV:L/AC:L/PR:N/UI:R/S:C/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:C)
Breaking this can reach past the original component and bite other resources—bigger blast radius.
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 6.0 [email protected]
4.6 2.0 MEDIUM
AV:L/AC:L/Au:N/C:P/I:P/A:P Click to expand
Access vector (AV:L)
Requires local access to the target system.
Access complexity (AC:L)
Exploitation conditions are straightforward and predictable.
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.
 3.9 6.4 [email protected]

Weakness enumeration for CVE-2021-3770

OS Trackers for CVE-2021-3770

vendor priority summary link
alpine high CVE-2021-3770: 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-2021-3770
debian not yet assigned CVE-2021-3770 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-2021-3770
gentoo low CVE-2021-3770: 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-2021-3770
redhat medium — https://access.redhat.com/security/cve/CVE-2021-3770
suse high CVE-2021-3770 severity important: SUSE including 5 source package names (gvim, vim, vim-data, vim-data-common, xxd), 97 product×package rows across 33 product lines (HPE Helion OpenStack 8, SUSE CaaS Platform 4.0, … (33 product lines)): Known Not Affected 97. https://www.suse.com/security/cve/CVE-2021-3770/
ubuntu medium CVE-2021-3770 medium priority: Ubuntu including 1 source packages (vim), 8 status rows across 8 suites (bionic, focal, hirsute, impish, jammy, trusty, upstream, xenial): released 5, not-affected 3. https://ubuntu.com/security/CVE-2021-3770

Affected software / configurations for CVE-2021-3770

Vendor Product Version Raw CPE
vim vim < 8.2.3408 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:*:*:*:*:*:*:*
netapp ontap_select_deploy_administration_utility — cpe:2.3:a:netapp:ontap_select_deploy_administration_utility:-:*:*:*:*:*:*:*

References for CVE-2021-3770

URL Tags
http://www.openwall.com/lists/oss-security/2021/10/01/1 Mailing List Patch Third Party Advisory
https://github.com/vim/vim/commit/b7081e135a16091c93f6f5f7525a5c58fb7ca9f9 Patch Third Party Advisory
https://huntr.dev/bounties/016ad2f2-07c1-4d14-a8ce-6eed10729365 Exploit Issue Tracking Patch Third Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/J2CJLY3CF55I2ULG2X4ENXLSXAXYW5J4/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/X4FFQARG3LGREPDZRI4C7ERQL3RJKEWQ/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ZFNTMVZCN4TRTTCAXRLVQ7H2P7FYAIZQ/
https://security.gentoo.org/glsa/202208-32 Third Party Advisory
https://security.netapp.com/advisory/ntap-20221124-0003/ Third Party Advisory
cvelogic Threat Intelligence