CVE-2025-59391

Memory disclosure via oversized OSCORE boolean value

Published Dec 8, 2025 · Updated Dec 8, 2025

Out-of-bounds read in libcoap before 4.3.5a allows local users to disclose memory or crash an application via a crafted OSCORE file. get_split_entry() passes an attacker-controlled boolean value length to memcmp() against the shorter literals "true" and "false". Exploitation requires a specially crafted local application to call coap_new_oscore_conf(); the standard library stores no keys or certificates.

CVSS severity6.5
Medium
EPSS probability0.26%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Out-of-bounds read in libcoap before 4.3.5a allows local users to disclose memory or crash an application via a crafted OSCORE file. get_split_entry() passes an attacker-controlled boolean value length to memcmp() against the shorter literals "true" and "false". Exploitation requires a specially crafted local application to call coap_new_oscore_conf(); the standard library stores no keys or certificates.

The record

CVE
CVE-2025-59391
Published
Dec 8, 2025
Updated
Dec 8, 2025
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-125
Attack vector
local
Privileges
Unavailable

Timeline

How it unfolded

  1. Dec 8, 2025CVE publishedPublication date reported by the CVE source.
  2. Dec 8, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectorlocal
Required privilegesUnavailable in this record.

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

6.5CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:L

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
PrivilegesUnavailable
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-125Out-of-bounds Read

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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