# ALAS2023-2026-2157: Security update for 5 packages

ALAS2023-2026-2157, released September 14, 2026, fixes 11 CVEs across 5 products. None of them is reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/fix/linux/alas2023-2026-2157
- Platform: Linux
- Released: Sep 14, 2026
- Priority: High (Closes CVE-2026-66046, high severity)
- CVEs: 11, exploited: 0, on CISA KEV: 0
- Vendor advisory: https://alas.aws.amazon.com/AL2023/ALAS-2026-2157.html

## Applies to

| Product | Release | Fixed in |
|---|---|---|
| [expat](https://patchblox.com/security/data/product/linux/expat.md) | amzn 2023 | 2.8.3-1.amzn2023.0.1 |
| [expat-debuginfo](https://patchblox.com/security/data/product/linux/expat-debuginfo.md) | amzn 2023 | 2.8.3-1.amzn2023.0.1 |
| [expat-debugsource](https://patchblox.com/security/data/product/linux/expat-debugsource.md) | amzn 2023 | 2.8.3-1.amzn2023.0.1 |
| [expat-devel](https://patchblox.com/security/data/product/linux/expat-devel.md) | amzn 2023 | 2.8.3-1.amzn2023.0.1 |
| [expat-static](https://patchblox.com/security/data/product/linux/expat-static.md) | amzn 2023 | 2.8.3-1.amzn2023.0.1 |

## CVEs this fix closes

| CVE | Priority | Title | CVSS | EPSS | Exploitation |
|---|---|---|---:|---:|---|
| [CVE-2026-66046](https://patchblox.com/security/data/cve/CVE-2026-66046.md) | High | Expat Denial of Service via storeAtts() Quadratic Complexity | 7.5 | 0.0074 |  |
| [CVE-2026-76957](https://patchblox.com/security/data/cve/CVE-2026-76957.md) | High | libexpat before 2.8.4 lacks handler call depth tracking with custom encoding callbacks. Thus, a use-after-free can occur. NOTE: this is similar to CVE-2026-50219, CVE-2026-56131 and CVE-2026-56412. | 7.8 | 0.0011 |  |
| [CVE-2026-50219](https://patchblox.com/security/data/cve/CVE-2026-50219.md) | Routine | libexpat before 2.8.2 lacks handler call depth tracking for calls to XML_GetBuffer, XML_Parse, XML_ParseBuffer, XML_ParserFree, or XML_ParserReset from within handlers in cases of a policy violation. Thus, a use-after-free can occur, | 6.9 | 0.0018 |  |
| [CVE-2026-56412](https://patchblox.com/security/data/cve/CVE-2026-56412.md) | Routine | libexpat before 2.8.2 does not consider XML_TOK_DATA_CHARS in doCdataSection and thus lacks handler call depth tracking for various calls from within handlers in cases of a policy violation. Thus, a use-after-free can occur. NOTE: this issue exists because of an incomplete fix for CVE-2026-50219. | 5.9 | 0.0018 |  |
| [CVE-2026-56131](https://patchblox.com/security/data/cve/CVE-2026-56131.md) | Routine | libexpat before 2.8.2 lacks handler call depth tracking for calls to XML_ResumeParser from within handlers in cases of a policy violation. Thus, a use-after-free can occur (similar to the CVE-2026-50219 situation). | 4.9 | 0.0018 |  |
| [CVE-2026-56404](https://patchblox.com/security/data/cve/CVE-2026-56404.md) | Routine | libexpat before 2.8.2 has an integer overflow in addBinding. | 6.9 | 0.0013 |  |
| [CVE-2026-56410](https://patchblox.com/security/data/cve/CVE-2026-56410.md) | Routine | xmlwf in libexpat before 2.8.2 has an integer overflow in resolveSystemId. | 6.9 | 0.0013 |  |
| [CVE-2026-56411](https://patchblox.com/security/data/cve/CVE-2026-56411.md) | Routine | xmlwf in libexpat before 2.8.2 has an integer overflow in endDoctypeDecl via NOTATION declarations. | 6.9 | 0.0013 |  |
| [CVE-2026-56405](https://patchblox.com/security/data/cve/CVE-2026-56405.md) | Routine | libexpat before 2.8.2 has an integer overflow in getAttributeId. | 6.9 | 0.0013 |  |
| [CVE-2026-56408](https://patchblox.com/security/data/cve/CVE-2026-56408.md) | Routine | expat: libexpat before 2.8.2 has an integer overflow in copyString. | 6.9 | 0.0013 |  |
| [CVE-2026-56409](https://patchblox.com/security/data/cve/CVE-2026-56409.md) | Routine | xmlwf in libexpat before 2.8.2 has an integer overflow for the output filename when -d outputDir is used. | 6.5 | 0.0012 |  |

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Data as of 2026-11-10T01:44:33Z 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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