# CVE-2025-59391: libcoap3: A memory disclosure vulnerability exists in libcoap's OSCORE configuration parser in libcoap before release-4.3.5-pat...

CVE-2025-59391 is fixed in 8 products on 1 platform, first by DEBIAN-CVE-2025-59391, released December 8, 2025. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2025-59391
- Priority: Routine
- CVSS: 6.5 (medium)
- EPSS: 0.0028
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Dec 8, 2025

## Description

A memory disclosure vulnerability exists in libcoap's OSCORE configuration parser in libcoap before release-4.3.5-patches. An out-of-bounds read may occur when parsing certain configuration values, allowing an attacker to infer or read memory beyond string boundaries in the .rodata section. This could potentially lead to information disclosure or denial of service.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | libcoap Fedora 43 | 4.3.5b-1.fc43 | [FEDORA-2026-0CE923A09D](https://patchblox.com/security/data/fix/linux/fedora-2026-0ce923a09d.md) | Apr 17, 2026 |
| Linux | libcoap-debuginfo Fedora 43 | 4.3.5b-1.fc43 | [FEDORA-2026-0CE923A09D](https://patchblox.com/security/data/fix/linux/fedora-2026-0ce923a09d.md) | Apr 17, 2026 |
| Linux | libcoap-debugsource Fedora 43 | 4.3.5b-1.fc43 | [FEDORA-2026-0CE923A09D](https://patchblox.com/security/data/fix/linux/fedora-2026-0ce923a09d.md) | Apr 17, 2026 |
| Linux | libcoap-devel Fedora 43 | 4.3.5b-1.fc43 | [FEDORA-2026-0CE923A09D](https://patchblox.com/security/data/fix/linux/fedora-2026-0ce923a09d.md) | Apr 17, 2026 |
| Linux | libcoap-doc Fedora 43 | 4.3.5b-1.fc43 | [FEDORA-2026-0CE923A09D](https://patchblox.com/security/data/fix/linux/fedora-2026-0ce923a09d.md) | Apr 17, 2026 |
| Linux | libcoap-utils Fedora 43 | 4.3.5b-1.fc43 | [FEDORA-2026-0CE923A09D](https://patchblox.com/security/data/fix/linux/fedora-2026-0ce923a09d.md) | Apr 17, 2026 |
| Linux | libcoap-utils-debuginfo Fedora 43 | 4.3.5b-1.fc43 | [FEDORA-2026-0CE923A09D](https://patchblox.com/security/data/fix/linux/fedora-2026-0ce923a09d.md) | Apr 17, 2026 |
| Linux | libcoap3 Debian 13.5 (trixie) | 4.3.4-1.1+deb13u2 | [DEBIAN-CVE-2025-59391](https://patchblox.com/security/data/fix/linux/debian-cve-2025-59391.md) | Dec 8, 2025 |
| Linux | libcoap3 Debian 14 | 4.3.5-2 | [DEBIAN-CVE-2025-59391](https://patchblox.com/security/data/fix/linux/debian-cve-2025-59391.md) | Dec 8, 2025 |

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Data as of 2026-11-09T01:18:40Z 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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