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CVE-2025-65495

HIGHCVSS 7.5/10EPSS 0.22%

Last modified

CVE-2025-65495 is a high-severity vulnerability rated 7.5/10 on the CVSS scale. 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.. EPSS estimates a 0.22% chance of exploitation in the next 30 days.

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.

Metrics

CVSS 3.1
7.5/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS Probability
0.22%

12.3th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

VendorProductVersions
LibcoapLibcoap4.3.5

References

Timeline

Published
Last Modified
Status
Analyzed

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 score of 7.5/10 (HIGH severity). The EPSS model estimates a 0.22% probability of exploitation in the next 30 days.
How do I fix CVE-2025-65495?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2025-65495?

Run a free Strix scan to check your systems for this vulnerability.

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Source: NVD / NIST