MediumPublic exploit

Vim helpfile Option Heap Buffer Overflow

IdentifiersCVE-2026-25749CWE-122· Heap-based Buffer Overflow

CVE-2026-25749 is a heap-based buffer overflow in Vim's help-tag file resolution logic. In versions before 9.1.2132, get_tagfname() in src/tag.c copies the user-controlled helpfile option into a heap allocation sized at MAXPATHL + 1 bytes, typically 4097 bytes, using STRCPY() without validating the input length. An oversized helpfile value overwrites heap memory when Vim processes help-file tags.

For your environment

Are you exposed to this one?

Mallory correlates every CVE against your assets, your vendors, and active adversary campaigns. Know which vulnerabilities matter for you, not just which ones are loud.

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ANALYST BRIEF

Impact, mitigation & remediation

What it means. What to do now. Patch path, mitigations, and the assume-compromise checklist.

Impact

What an attacker gets, and what they’ve been doing with it.

Successful exploitation corrupts heap memory and can permit arbitrary code execution in the security context of the Vim process. The memory corruption may also cause Vim to terminate unexpectedly.

Mitigation

If you can’t patch tonight, do this now.

Until updates can be deployed, prevent untrusted parties from controlling the helpfile option and avoid processing help-tag data in sessions where that option may contain an untrusted or oversized value.

Remediation

Patch, then assume compromise.

Upgrade Vim to version 9.1.2132 or later. For vendor-maintained distributions, apply the vendor security update containing the backported fix; affected Red Hat package updates address this issue.

PUBLIC EXPLOITS

Exploits

No public exploits tracked yet. Mallory keeps watching.

VALID 0 / 0 TOTALView more in app

No public exploit code observed for this vulnerability.

EXPOSURE SURFACE

Affected products & vendors

Products and vendors Mallory has correlated with this vulnerability. Open in Mallory to drill down to specific CPE configurations and version ranges.

VendorProductType

NeovimNeovimapplication

VimVimapplication

Vendor-confirmed product mapping. Mallory continuously reconciles this list against your asset inventory.

ACTIVITY FEED

Recent activity

23 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.

23 SOURCESView more in app

redhat accessNews

May 20, 2026

RHSA-2026:17596 - Security Advisory - Red Hat Customer Portal

A Vim vulnerability in helpfile option processing that permits arbitrary code execution.

redhat accessNews

May 13, 2026

RHSA-2026:15087 - Security Advisory - Red Hat Customer Portal

A Vim arbitrary code execution vulnerability via helpfile option processing.

redhat accessNews

May 13, 2026

RHSA-2026:14773 - Security Advisory - Red Hat Customer Portal

A Vim arbitrary code execution vulnerability via helpfile option processing.

redhat accessNews

May 8, 2026

RHSA-2026:12274 - Security Advisory - Red Hat Customer Portal

An arbitrary-code-execution vulnerability in Vim caused by processing of the helpfile option.

+14 more in the timeline

What this page doesn’t show

The version that knows your environment.

This page is what’s public. Mallory adds the parts that aren’t: which of your assets are affected, which adversaries are exploiting it right now, which detections to deploy, and what to do tonight.

Start free trial

Exposure mapping

Query your assets running an affected version, and investigate the blast radius.

Threat actor evidence

Every observed campaign linking this CVE to a named adversary.

Associated malware

Malware families riding this exploit, with evidence and IOCs.

Detection signatures

YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.

Vendor-by-vendor mapping

Cross-references every affected SKU, including bundled OEM variants.

Social activity2

Community discussion across Reddit, Mastodon, and other social sources.

EXTERNAL REFERENCES

MITRE CVE

cve.org · CVE-2026-25749

NVD

nvd.nist.gov/vuln/detail/CVE-2026-25749

MITRE CWE · CWE-122

Heap-based Buffer Overflow

Patch

github.com/vim/vim/commit/0714b15940b245108e6e9d7aa2260dd849a26fa9

Patch

github.com/vim/vim/security/advisories/GHSA-5w93-4g67-mm43

Product

github.com/vim/vim/releases/tag/v9.1.2132

Back to vulnerabilities

MediumPublic exploit

Vim helpfile Option Heap Buffer Overflow

IdentifiersCVE-2026-25749CWE-122· Heap-based Buffer Overflow

For your environment

Are you exposed to this one?

Mallory correlates every CVE against your assets, your vendors, and active adversary campaigns. Know which vulnerabilities matter for you, not just which ones are loud.

Start free trial

ANALYST BRIEF

Impact, mitigation & remediation

What it means. What to do now. Patch path, mitigations, and the assume-compromise checklist.

Impact

What an attacker gets, and what they’ve been doing with it.

Successful exploitation corrupts heap memory and can permit arbitrary code execution in the security context of the Vim process. The memory corruption may also cause Vim to terminate unexpectedly.

Mitigation

If you can’t patch tonight, do this now.

Remediation

Patch, then assume compromise.

Upgrade Vim to version 9.1.2132 or later. For vendor-maintained distributions, apply the vendor security update containing the backported fix; affected Red Hat package updates address this issue.

PUBLIC EXPLOITS

Exploits

No public exploits tracked yet. Mallory keeps watching.

VALID 0 / 0 TOTALView more in app

No public exploit code observed for this vulnerability.

EXPOSURE SURFACE

Affected products & vendors

Products and vendors Mallory has correlated with this vulnerability. Open in Mallory to drill down to specific CPE configurations and version ranges.

VendorProductType

NeovimNeovimapplication

VimVimapplication

Vendor-confirmed product mapping. Mallory continuously reconciles this list against your asset inventory.

ACTIVITY FEED

Recent activity

23 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.

23 SOURCESView more in app

redhat accessNews

May 20, 2026

RHSA-2026:17596 - Security Advisory - Red Hat Customer Portal

A Vim vulnerability in helpfile option processing that permits arbitrary code execution.

redhat accessNews

May 13, 2026

RHSA-2026:15087 - Security Advisory - Red Hat Customer Portal

A Vim arbitrary code execution vulnerability via helpfile option processing.

redhat accessNews

May 13, 2026

RHSA-2026:14773 - Security Advisory - Red Hat Customer Portal

A Vim arbitrary code execution vulnerability via helpfile option processing.

redhat accessNews

May 8, 2026

RHSA-2026:12274 - Security Advisory - Red Hat Customer Portal

An arbitrary-code-execution vulnerability in Vim caused by processing of the helpfile option.

+14 more in the timeline

What this page doesn’t show

The version that knows your environment.

Start free trial

Exposure mapping

Query your assets running an affected version, and investigate the blast radius.

Threat actor evidence

Every observed campaign linking this CVE to a named adversary.

Associated malware

Malware families riding this exploit, with evidence and IOCs.

Detection signatures

YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.

Vendor-by-vendor mapping

Cross-references every affected SKU, including bundled OEM variants.

Social activity2

Community discussion across Reddit, Mastodon, and other social sources.

EXTERNAL REFERENCES

MITRE CVE

cve.org · CVE-2026-25749

NVD

nvd.nist.gov/vuln/detail/CVE-2026-25749

MITRE CWE · CWE-122

Heap-based Buffer Overflow

Patch

github.com/vim/vim/commit/0714b15940b245108e6e9d7aa2260dd849a26fa9

Patch

github.com/vim/vim/security/advisories/GHSA-5w93-4g67-mm43

Product

github.com/vim/vim/releases/tag/v9.1.2132