# CVE-2026-115506: libexpat through 2.9.0 Denial of Service via Billion Laughs Detection Delay

CVE-2026-115506 is fixed in 8 products on 1 platform, first by DEBIAN-CVE-2026-115506, released November 9, 2026. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2026-115506
- Priority: High
- CVSS: 7.5 (Important)
- EPSS: 0.0045
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Oct 22, 2026
- Weakness: Improper Restriction of Recursive Entity References in DTDs ('XML Entity Expansion')
- Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-115506

## Description

mingw-expat: expat: Denial of Service via delayed entity amplification detection

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | expat Debian 14 | 2.10.0-1 | [DEBIAN-CVE-2026-115506](https://patchblox.com/security/data/fix/linux/debian-cve-2026-115506.md) | Nov 9, 2026 |
| Linux | mingw-expat Fedora 43 | 2.9.0-1.fc43 | [FEDORA-2026-A83294F5AB](https://patchblox.com/security/data/fix/linux/fedora-2026-a83294f5ab.md) | Nov 9, 2026 |
| Linux | mingw32-expat Fedora 43 | 2.9.0-1.fc43 | [FEDORA-2026-A83294F5AB](https://patchblox.com/security/data/fix/linux/fedora-2026-a83294f5ab.md) | Nov 9, 2026 |
| Linux | mingw32-expat-debuginfo Fedora 43 | 2.9.0-1.fc43 | [FEDORA-2026-A83294F5AB](https://patchblox.com/security/data/fix/linux/fedora-2026-a83294f5ab.md) | Nov 9, 2026 |
| Linux | mingw32-expat-static Fedora 43 | 2.9.0-1.fc43 | [FEDORA-2026-A83294F5AB](https://patchblox.com/security/data/fix/linux/fedora-2026-a83294f5ab.md) | Nov 9, 2026 |
| Linux | mingw64-expat Fedora 43 | 2.9.0-1.fc43 | [FEDORA-2026-A83294F5AB](https://patchblox.com/security/data/fix/linux/fedora-2026-a83294f5ab.md) | Nov 9, 2026 |
| Linux | mingw64-expat-debuginfo Fedora 43 | 2.9.0-1.fc43 | [FEDORA-2026-A83294F5AB](https://patchblox.com/security/data/fix/linux/fedora-2026-a83294f5ab.md) | Nov 9, 2026 |
| Linux | mingw64-expat-static Fedora 43 | 2.9.0-1.fc43 | [FEDORA-2026-A83294F5AB](https://patchblox.com/security/data/fix/linux/fedora-2026-a83294f5ab.md) | Nov 9, 2026 |

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Data as of 2026-11-11T07:45:43Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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