How severe is CVE-2025-65495?

CVE-2025-65495 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2025-65495 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (12th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2025-65495?

CVE-2025-65495 affects Libcoap. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2025-65495?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

Does CVE-2025-65495 have an EU (EUVD) identifier?

Yes. CVE-2025-65495 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-198714.

When was CVE-2025-65495 published?

CVE-2025-65495 was published on 2025-11-24 and last updated on 2026-06-17.

CVE-2025-65495

CVE-2025-65495 is a high-severity vulnerability in Libcoap with a CVSS 3.x base score of 7.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-195.

Key facts

Severity: High (CVSS 3.x base score 7.5)
EPSS exploit prediction: 0% (12th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2025-198714
Weakness: CWE-195
Affected product: Libcoap
Published: 2025-11-24
Last modified: 2026-06-17

Description

Integer signedness error in tls_verify_call_back() in src/coap_openssl.c in OISM libcoap 4.3.5 allows remote attackers to cause a denial of service via a crafted TLS certificate that causes i2d_X509() to return -1 and be misused as a malloc() size parameter.

Frequently asked questions

What is CVE-2025-65495?: Integer signedness error in tls_verify_call_back() in src/coap_openssl.c in OISM libcoap 4.3.5 allows remote attackers to cause a denial of service via a crafted TLS certificate that causes i2d_X509() to return -1 and be misused as a malloc() size parameter.
How severe is CVE-2025-65495?: CVE-2025-65495 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2025-65495 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (12th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2025-65495?: CVE-2025-65495 affects Libcoap. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2025-65495?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2025-65495 have an EU (EUVD) identifier?: Yes. CVE-2025-65495 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-198714.
When was CVE-2025-65495 published?: CVE-2025-65495 was published on 2025-11-24 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:libcoap:libcoap:4.3.5:-:*:*:*:*:*:*

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