CVE-2019-1124

published 2019-07-15

CVE-2019-1124: A remote code execution vulnerability exists in the way that DirectWrite handles objects in memory, aka 'DirectWrite Remote Code Execution Vulnerability'. This…

Priority P2 66 high 8.8 CVSS 3.0

AV N AC L PR N UI R S U C H I H A H

EXPLOIT

A remote code execution vulnerability exists in the way that DirectWrite handles objects in memory, aka 'DirectWrite Remote Code Execution Vulnerability'. This CVE ID is unique from CVE-2019-1117, CVE-2019-1118, CVE-2019-1119, CVE-2019-1120, CVE-2019-1121, CVE-2019-1122, CVE-2019-1123, CVE-2019-1127, CVE-2019-1128.

Affected

36 ranges · showing 25

Vendor	Product	Version range	Fixed in
microsoft	windows	—	—
microsoft	windows	—	—
microsoft	windows	—	—
microsoft	windows	—	—
microsoft	windows	—	—
microsoft	windows	—	—
microsoft	windows	—	—
microsoft	windows	—	—
microsoft	windows	—	—
microsoft	windows_10	—	—
microsoft	windows_10	—	—
microsoft	windows_10	—	—
microsoft	windows_10	—	—
microsoft	windows_10_version_1903_for_32-bit_systems	—	—
microsoft	windows_10_version_1903_for_arm64-based_systems	—	—
microsoft	windows_10_version_1903_for_x64-based_systems	—	—
microsoft	windows_server	—	—
microsoft	windows_server	—	—
microsoft	windows_server	—	—
microsoft	windows_server_2016	—	—
microsoft	windows_server_2016	—	—
msrc	windows_10_version_1709_for_32-bit_systems	—	—
msrc	windows_10_version_1709_for_arm64-based_systems	—	—
msrc	windows_10_version_1709_for_x64-based_systems	—	—
msrc	windows_10_version_1803_for_32-bit_systems	—	—

Detection & IOCs extracted from sources · hover to see the quote

filename poc.otf↗

• → Detect OpenType/CFF fonts with empty or null-prefixed ROS (Registry/Ordering/Supplement) strings — specifically Registry or Ordering strings beginning with a null byte (e.g. '\0dobe', '\0dentity') — which trigger the AFDKO cfwSindexAssignSID OOB read/write via SRI_UNDEF (0xffff) index. ↗
• → Monitor Microsoft Edge renderer process crashes in DWrite!cfwSindexAssignSID with rcx=0xffff (index=65535), indicating exploitation attempt of the OOB read/write via crafted OpenType font during printing (to PDF, XPS, or physical printer). ↗
• → The vulnerability is reachable via the Direct2D printing interface in Microsoft Edge — monitor for Edge renderer processes invoking d2d1!dxc::TextConvertor::InstanceFontResources or dwrite!DWriteFactory::CreateInstancedStream when processing web pages with embedded OpenType variable fonts during print operations. ↗

• · The AFDKO code is reached through CreateInstancedStream, which is not a public COM interface — the confirmed trigger path is via Direct2D printing (d2d1!dxc::TextConvertor::InstanceFontResources); other trigger paths may exist but were not confirmed at time of disclosure. ↗

CVSS provenance

nvd v3.0 8.8 HIGH CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

nvd v2.0 9.3 CRITICAL AV:N/AC:M/Au:N/C:C/I:C/A:C

vendor_msrc 7.8 HIGH

CVEs like this are exactly what “Exploited This Week” covers.

Every Monday: what got weaponized or added to CISA KEV in the last seven days — each CVE cross-linked to its PoC, Nuclei template, and detection rule. Free, one email a week, unsubscribe in one click.