# OPENSUSE-SU-2026:21945-1: expat security update

OPENSUSE-SU-2026:21945-1, released September 24, 2026, fixes 17 CVEs in expat (version 2.8.4-160000.1.1). None of them is reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/fix/linux/opensuse-su-2026-21945-1
- Platform: Linux
- Released: Sep 24, 2026
- Priority: High (Closes CVE-2026-66046, high severity)
- CVEs: 17, exploited: 0, on CISA KEV: 0
- Vendor advisory: https://osv.dev/vulnerability/openSUSE-SU-2026:21945-1

## Applies to

| Product | Release | Fixed in |
|---|---|---|
| [expat](https://patchblox.com/security/data/product/linux/expat.md) | opensuse-leap 16.0 | 2.8.4-160000.1.1 |

## 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-2026-45186](https://patchblox.com/security/data/cve/CVE-2026-45186.md) | High | In libexpat before 2.8.1, the computational complexity of attribute name collision checks allows a denial of service via moderately sized crafted XML input. | 8.2 | 0.0048 |  |
| [CVE-2026-76956](https://patchblox.com/security/data/cve/CVE-2026-76956.md) | High | In libexpat 2.8.2 and 2.8.3 before 2.8.4, misinterpretation of getentropy's return code leads to insufficient entropy, which results in being vulnerable to hash flooding attacks, causing a denial of service via crafted XML content. | 7.5 | 0.0029 |  |
| [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-2026-41080](https://patchblox.com/security/data/cve/CVE-2026-41080.md) | Routine | expat: libexpat before 2.8.0 uses insufficient entropy, and thus hash flooding can occur via a crafted XML document. | 2.9 | 0.0040 |  |
| [CVE-2026-76641](https://patchblox.com/security/data/cve/CVE-2026-76641.md) | Routine | expat: Expat through 2.8.3 contains an out-of-bounds read vulnerability that allows attackers to trigger memory corruption b... | n/a | 0.0035 |  |
| [CVE-2026-72522](https://patchblox.com/security/data/cve/CVE-2026-72522.md) | Routine | libexpat before 2.8.3 has an out-of-bounds read and resultant infinite loop because low surrogates are treated the same as high surrogates during Unicode processing in the *_toUtf16 functions. | 6.2 | 0.0019 |  |
| [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-2026-56406](https://patchblox.com/security/data/cve/CVE-2026-56406.md) | Routine | libexpat before 2.8.2 has an integer overflow in XML_ParseBuffer because it lacked a check that was present in XML_Parse. | 6.9 | 0.0017 |  |
| [CVE-2026-56407](https://patchblox.com/security/data/cve/CVE-2026-56407.md) | Routine | libexpat before 2.8.2 has an integer overflow in doProlog that is related to storeEntityValue and entity textLen. | 6.9 | 0.0017 |  |
| [CVE-2026-56132](https://patchblox.com/security/data/cve/CVE-2026-56132.md) | Routine | In libexpat before 2.8.2, there is a heap-based buffer overflow in doProlog in xmlparse.c because scaffold backing array reallocation is mishandled when there is data-structure sharing across parsers. | 6.9 | 0.0014 |  |
| [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-2026-56408](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 2026-11-10T07:50:38Z 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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