Out-of-Bounds Write in Vim (CVE-2026-55693)
Summary
Out-of-bounds write in Vim (CVE-2026-55693). Successful exploitation can lead to full system takeover. Mitigation: upgrade to 9.2.0653 or later.
Original description
The description as published by the source.
Vim is an open source, command line text editor. Prior to 9.2.0653, the tree_count_words() function in src/spellfile.c fills in the word-count fields of a spell-file word trie by walking it iteratively with a depth counter. The counter is bounded only by the trie structure itself; it is never checked against the size of the fixed MAXWLEN-element stack arrays it indexes (arridx[], curi[], wordcount[]). A crafted .spl/.sug file pair, loaded when the user invokes spell suggestion, can drive the descent arbitrarily deep, so the function writes past the end of those arrays. This is a stack out-of-bounds write that corrupts the call frame and crashes the editor. This vulnerability is fixed in 9.2.0653.
Source: NIST National Vulnerability Database NVD
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-55693 has been found in Vim.
Successful exploitation can lead to full system takeover. CVSS score: 7.8/10.
What to do: upgrade Vim to 9.2.0653 or later.
If unsure, ask your IT team or search "Vim CVE-2026-55693" on the vendor's site.
CVE-2026-55693 (Vim) — CWE-787 / CVSS v3 7.8
Attack vector: local / unauthenticated
Patched: 9.2.0653 — apply immediately
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
Out-of-bounds write (CWE-787) exists in Vim.
Check the vendor advisory for the affected versions of Vim.
Severity: High (CVSS 7.8/10). Successful exploitation can lead to full system takeover.
Update to 9.2.0653.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'Vim' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
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1Identify exposure identify
grep -r 'Vim' . | grep -v node_modulesリポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で
Vimを grep し、稼働しているサービス・バージョンを把握する。 -
2Apply patch patch
Upgrade Vim to 9.2.0653ステージング環境で 9.2.0653 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスを含めること。
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3Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。
Fix status by distribution
Fixed packages published by each distribution for this CVE
- Debian DEBIAN-CVE-2026-55693 vim
- Ubuntu UBUNTU-CVE-2026-55693 vim Fixed in: 2:7.4.052-1ubuntu3.1+esm30