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Stack-based Buffer OverflowWeakness · CWE-121

CVE-2026-40489

HIGH · 8.6 CVSS v4.0 Published 2026-04-18
Patch available
A vendor patch is available. No clean upgrade release — apply the published patch.
See remediation →
91/100
Remediation priority · Urgent
No privileges Zero-click Patch available

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
editorconfig-core-c is an EditorConfig core library for use by plugins supporting EditorConfig parsing. Versions up to and including 0.12.10 have a stack-based buffer overflow in ec_glob() that allows an attacker to crash any application using libeditorconfig by providing a specially crafted directory structure and .editorconfig file. This is an incomplete fix for CVE-2023-0341. The pcre_str buffer was protected in 0.12.6 but the adjacent l_pattern[8194] stack buffer received no equivalent protection. On Ubuntu 24.04, FORTIFY_SOURCE converts the overflow to SIGABRT (DoS). Version 0.12.11 contains an updated fix.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis
How this class of weakness works · CWE-121

Data overflows a fixed-size buffer allocated on the stack, overwriting adjacent stack memory — including saved return addresses — which is the classic route to redirecting execution into attacker-supplied code. Crafted input is all it takes. Remediation is strict length checks, safe bounded string and memory functions, and modern stack-protection mitigations.

General guidance for the stack-based buffer overflow class — the official description and references above are authoritative for this specific CVE. Want a bespoke review and a reviewed fix? Ask our team →

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Local
Complexity
Low
Privileges
None
Authentication
X
User interaction
None
Scope
X

CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Patch available Apply the vendor patch
Vendor patch github.com →
Recommended fix High confidence

editorconfig-core-c version 0.12.11

  1. Obtain editorconfig-core-c version 0.12.11 from the official repository at https://github.com/editorconfig/editorconfig-core-c
  2. Upgrade your installation of editorconfig-core-c to version 0.12.11 or later
  3. Rebuild and redeploy any applications or plugins that link against libeditorconfig

Generated from the published advisory — verify against the referenced sources before acting.

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-40489 in production — separate from our analysis above.

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What this is

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What belongs here
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  • Version or environment caveats, and links to real fixes
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