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.
Conclusion & alert: CVE-2025-59391 is rated Low Risk (32.9/100): CVSS Medium severity, with low exploitation likelihood (EPSS 0.06%). Mandatory action: Monitor for updates and reassess as exploit intelligence or EPSS changes.
Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.
EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).
| # | Date | Old EPSS score | New EPSS score | Delta (New - Old) |
|---|---|---|---|---|
| 1 | 2026-01-18 | 0.03% | 0.06% | +0.03% |
| 2 | 2025-12-09 | — | 0.03% | — |
Full EPSS history (2 records total)
CVSS metrics for this CVE.
| Base score | Version | Severity | Vector | Exploitability | Impact | Score source |
|---|---|---|---|---|---|---|
| 6.5 | 3.1 | MEDIUM |
|
3.9 | 2.5 | 134c704f-9b21-4f2e-91b3-4a467353bcc0 |
| vendor | priority | summary | link |
|---|---|---|---|
debian
|
not yet assigned | CVE-2025-59391 not yet assigned priority: Debian including 1 source packages (libcoap3), 4 status rows across 4 suites (bookworm, forky, sid, trixie): resolved 3, open 1. | https://security-tracker.debian.org/tracker/CVE-2025-59391 |
ubuntu
|
medium | CVE-2025-59391 medium priority: Ubuntu including 3 source packages (libcoap, libcoap2, libcoap3), 17 status rows across 7 suites (bionic, focal, jammy, noble, plucky, questing, upstream): needs-triage 9, DNE 7, ignored 1. | https://ubuntu.com/security/CVE-2025-59391 |
| URL | Tags |
|---|---|
| https://github.com/obgm/libcoap/pull/1730 | Issue Tracking Patch |
| https://github.com/obgm/libcoap/releases/tag/v4.3.5a | Release Notes |