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Vulnerabilities

Vulnerability · CVE-2025-65500

NULL pointer dereference in coap_dtls_generate_cookie() in src/coap_openssl.c in OISM libcoap 4.3.5 allows remote attackers to cause a denial of service via a crafted DTLS handshak

Published Nov 24, 2025 · catalog updated Nov 24, 2025 · NULL pointer dereference in

Last checked Oct 31, 2026. A connected source was read within the last 7 days.

Check if you run it

No confirmed exploitation is on record for CVE-2025-65500. EPSS is 0.28%. Act only if a listed version of NULL pointer dereference in is installed.

Gaps on this record

  • The stored product name is a package slug. The name on this page is taken from the title (NULL pointer dereference in).
  • No version range is stored. A customer cannot check an installed version against this record.
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.

Same product and reporting

Severity
Medium4.3
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.28%
Remediation
Vendor / distro source
Affected products
vendor n/a n/a n/a

NULL pointer dereference in coap_dtls_generate_cookie() 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_SSL_CTX() to return NULL.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • vendor n/a n/a n/an/a

How to fix CVE-2025-65500

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2025-65500. EPSS is 0.28%. Act only if a listed version of NULL pointer dereference in is installed.

Which versions are affected?

Compare what you have installed with n/a n/a n/a n/a. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

No weakness class is stored. EPSS 0.28%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Technology hubs

OpenSSL security

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Nov 24, 2025 · EUVD

    Detected

    NULL pointer dereference in coap_dtls_generate_cookie() 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_SSL_CTX() to return NULL.

  2. Nov 24, 2025 · EUVD

    Updated

    NULL pointer dereference in coap_dtls_generate_cookie() 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_SSL_CTX() to return NULL.

Sources

  • CVE.orgVulnerability recordCVE-2025-65500

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2025-65500

    30-day exploitation probability 0.28%

    first.org
  • EUVDVulnerability recordEUVD-2025-198708

    NULL pointer dereference in coap_dtls_generate_cookie() 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_SSL_CTX() to return NULL.

    euvd.enisa.europa.eu

References

Freshness

Last verified in this catalog Oct 31, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.

  • FIRST EPSSOct 31, 2026
  • CVE.orgOct 28, 2026
  • EUVDOct 28, 2026