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CVE-2026-68499 medium CVSS 6.2

Vulnerability in re2 (CVE-2026-68499)

Summary

Vulnerability in re2 (CVE-2026-68499). Risk of unauthorized operations or information disclosure. Exploitable via String.prototype.match. Mitigation: upgrade to 1.25.2 or later.

Original description

The description as published by the source.

Summary

String.prototype.match with a global RE2 collects all matches in a native loop that advances the cursor by the match length. A zero-width (empty) match has length 0, so the cursor never advances: the same empty match is found forever and appended to an ever-growing native vector. Any pattern that can match the empty string (a*, b?, x{0,3}, (a)|, (?:), …) therefore causes an infinite loop with unbounded memory growth. The call is synchronous native code, so it blocks the entire event loop and cannot be interrupted by try/catch, AbortController, --max-old-space-size, or timers — the process must be killed externally. This diverges from the built-in engine, where 'xxxx'.match(/a*/g) returns a finite array.

Root cause

// lib/match.cc:44 — global branch of WrappedRE2::Match
while (re2->regexp.Match(str, byteIndex, str.size, anchor, &match, 1)) {
    groups.push_back(match);
    byteIndex = match.data() - str.data + match.size();   // += 0 for a zero-width match
}

When match.size() == 0, byteIndex is unchanged, so the next iteration matches the same empty position again; groups grows without bound. The other iteration paths already guard this: lib/split.cc:50-55 advances by getUtf8CharSize on an empty match, and exec advances lastIndex. Only this global Match loop is missing the guard.

Proof of concept

const RE2 = require('re2');
'x'.match(new RE2('a*', 'g'));   // never returns; grows memory unti…

Source: NIST National Vulnerability Database NVD GitHub Advisory

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-2026-68499 has been found in re2.
Attackers can target a specific entry point like String.prototype.match over the network to misuse the product.
Risk of unauthorized operations or information disclosure. CVSS score: 6.2/10.
What to do: upgrade re2 to 1.25.2 or later.
If unsure, ask your IT team or search "re2 CVE-2026-68499" on the vendor's site.

CVE-2026-68499 (re2) — CWE-835 / CVSS v3 6.2
Attack vector: local / unauthenticated / no user interaction
Attack surface: String.prototype.match / RE2 / AbortController / byteIndex
Patched: 1.25.2 — 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.

❓ What is the problem

A vulnerability (CWE-835) exists in re2. Attackers reach the vulnerable code path via String.prototype.match without authentication.

📍 Affected scope

Check the vendor advisory for the affected versions of re2. Attack surface: String.prototype.match / RE2 / AbortController / byteIndex.

🔥 Severity

Severity: Medium (CVSS 6.2/10). Risk of unauthorized operations or information disclosure.

🔧 How to fix

Update to 1.25.2.

🛡️ Workaround

Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.

🔍 Detection

Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 're2' . 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

  1. 1
    Identify exposure identify 
    grep -r 're2' . | 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 re2 を grep し、稼働しているサービス・バージョンを把握する。

  2. 2
    Apply patch patch 
    Upgrade re2 to 1.25.2

    ステージング環境で 1.25.2 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。

  3. 3
    Post-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。

Affected packages

npm re2
[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"1.25.2"}]}]

Fix status by distribution

Fixed packages published by each distribution for this CVE

References

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