Raw vector
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:LSummary
CVE-2026-28421 is a medium-severity Improper Input Validation (CWE-20) vulnerability in Vim Vim. Its CVSS base score is 5.3 (Medium).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Privilege Escalation (T1068); ranked at the 7th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
The strongest mitigations our analysis identified map to SA-11 (Developer Testing and Evaluation) and SI-10 (Information Input Validation) — see the control section below for these in your framework.
Deeper analysis AI-assisted summary
Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.
CVE-2026-28421 is a vulnerability in Vim, an open source command-line text editor, affecting versions prior to 9.2.0077. It involves a heap buffer overflow and a segmentation fault in Vim's swap file recovery logic, triggered by unvalidated fields read from crafted pointer blocks within a swap file. The issues are classified under CWE-20 (Improper Input Validation) and CWE-122 (Heap-based Buffer Overflow), with a CVSS v3.1 base score of 5.3 (AV:L/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:L).
An attacker with local access can exploit this vulnerability by crafting a malicious swap file and tricking a user into recovering it via Vim's recovery mechanism, which requires user interaction but no special privileges. Successful exploitation could result in limited impacts, including low-level disclosure of sensitive information, minor modification of data, or a denial of service through application crash.
Vim version 9.2.0077 addresses the vulnerability with fixes detailed in the associated GitHub commit (65c1a143c331c886dc28) and release notes. The GitHub security advisory (GHSA-r2gw-2x48-jj5p) and an oss-security mailing list post from February 27, 2026, recommend updating to the patched version to mitigate the risks.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-9089
Vulnerability Data
Vim is an open source, command line text editor. Versions prior to 9.2.0077 have a heap-buffer-overflow and a segmentation fault (SEGV) exist in Vim's swap file recovery logic. Both are caused by unvalidated fields read from crafted pointer blocks within…
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a swap file. Version 9.2.0077 fixes the issue.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Control response
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- 6 hardening rules · 3 OS baselines
V1.4.1
Mitigating Controls (NIST 800-53 r5) AI
Developer testing and evaluation can discover missing input validation through analysis or test cases.
SI-10 directly requires validity checks on information inputs, structurally preventing improper or missing validation.
Requiring documented development standards and tools can embed input-validation practices into the engineering process.
Security engineering principles require use of memory-safe constructs and bounds-checked allocation routines that avoid introducing heap overflows.
Memory-protection mechanisms limit the ability of a heap overflow to execute attacker-controlled code or corrupt adjacent structures.
Mitigating Controls (NIST CSF 2.0) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.
Secure-development practices directly require bounds checking and safe memory handling that prevent heap overflows.
Vulnerability scanning and recording can discover heap-overflow flaws but does not prevent their introduction in code.
Timely patching removes known heap-overflow instances after they exist.
Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.
Testing against a defined set of requirements and using code review plus vulnerability scanning forces validation of inputs and handling of unanticipated conditions, reducing the chance that malformed data will be accepted.
Secure-coding guidelines and mandatory security testing (including code scans) compel developers to validate and sanitize inputs at design and implementation time, lowering the incidence of malformed or malicious data reaching downstream components.
Mandating input controls that include integrity checks and input validation ensures that untrusted data is examined before use, blocking the root cause of many injection and malformed-data weaknesses.
Security-by-design principles explicitly call for data validation and sanitization at every layer, reducing the chance that malformed or malicious input will be processed without scrutiny.
Requiring language-specific secure coding standards, peer review, SAST and documented mitigation of common programming errors forces validation of all inputs before they are trusted.
Change management ensures controlled deployment of fixes for discovered heap-overflow vulnerabilities.
Hardening callouts derived
Configuration rules from DISA STIG baselines that bear on weaknesses of the type cited by this CVE. Each rule is shown with the relationship its mapping actually records, against the CWE it was authored against. Derived via CVE→CWE over `controls_xwalks` (authoritative rows only; rows rated `none` are excluded).
RHEL 8 (1 rule)
- V-230265 RHEL 8 must prevent the installation of software, patches, service packs, device drivers, or operating system components of local packages without verification they have been digitally signed using a certificate that is issued by a Certificate Authority (CA) that is recognized and approved by the organization. prevents CWE-20