How severe is CVE-2025-65499?

CVE-2025-65499 has a CVSS 3.x base score of 4.3, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is none, integrity none, and availability low.

Is CVE-2025-65499 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (13th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2025-65499?

CVE-2025-65499 affects Libcoap. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2025-65499?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

Does CVE-2025-65499 have an EU (EUVD) identifier?

Yes. CVE-2025-65499 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-198711.

When was CVE-2025-65499 published?

CVE-2025-65499 was published on 2025-11-24 and last updated on 2026-06-17.

CVE-2025-65499

CVE-2025-65499 is a medium-severity vulnerability in Libcoap with a CVSS 3.x base score of 4.3. 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-129.

Key facts

Severity: Medium (CVSS 3.x base score 4.3)
EPSS exploit prediction: 0% (13th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2025-198711
Weakness: CWE-129
Affected product: Libcoap
Published: 2025-11-24
Last modified: 2026-06-17

Description

Array index 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 DTLS handshake that triggers SSL_get_ex_data_X509_STORE_CTX_idx() to return -1.

Frequently asked questions

What is CVE-2025-65499?: Array index 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 DTLS handshake that triggers SSL_get_ex_data_X509_STORE_CTX_idx() to return -1.
How severe is CVE-2025-65499?: CVE-2025-65499 has a CVSS 3.x base score of 4.3, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is none, integrity none, and availability low.
Is CVE-2025-65499 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (13th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2025-65499?: CVE-2025-65499 affects Libcoap. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2025-65499?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2025-65499 have an EU (EUVD) identifier?: Yes. CVE-2025-65499 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-198711.
When was CVE-2025-65499 published?: CVE-2025-65499 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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