Libcoap
CVE-2025-65497
MEDIUM
Vulnerability Assessment
| Weakness |
CWE
OWASP Top 10:2025
A10:2025 - Mishandling of Exceptional Conditions
ASVS 5.0
V16 - Security Logging and Error Handling Null pointer safety, defensive checks
MITRE ATT&CK
1 technique across 1 tactic: Impact The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up. |
| Impact | CVSS score of 4.3 (MEDIUM). Attack characteristics: network attack vector, low complexity, no privileges required, user interaction required. EPSS exploitation probability: 0.24%. |
| Exploit ScenarioDerived | A remote attacker could crash the application by dereferencing a null pointer by sending crafted requests to the affected application. No authentication is required to exploit this vulnerability. |
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Alert meAnalysisAIv1 – Mar 28, 2026
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. Rated medium severity (CVSS 4.3), this vulnerability is remotely exploitable, no authentication required, low attack complexity.
RemediationAI
A vendor patch is available. Apply the latest security update as soon as possible. Check pointers before dereferencing. Use static analysis tools to detect null pointer paths.
Affects your stack
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Technical ContextAI · show details
This vulnerability is classified as NULL Pointer Dereference (CWE-476), which allows attackers to crash the application by dereferencing a null pointer. 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. Affected products include: Libcoap.
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- Exploit and PoC references, threat intelligence from 22 sources
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Severity by source
AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L
Primary rating from NVD.
CVSS VectorNVD
Lifecycle Timeline
2DescriptionCVE.org
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.
Executive ViewAI
CVE-2025-65497 presents moderate security risk, a null pointer dereference vulnerability rated CVSS 4.3. Exploitation could compromise the security of affected deployments. A patch is available and should be applied during regular vulnerability management.
Apply vendor patch. If patching is delayed: enable ASLR/DEP, apply network segmentation.
Threat Intelligence Overview
How this decision was reached
The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.
What every action level means
SSVC AssessmentENISA
Priority Score
Attack Technique
A null pointer dereference occurs when a program attempts to access memory through a pointer that has been set to NULL (address 0x0).
Denial of Service attacks render applications or systems unavailable by overwhelming resources or triggering failure conditions.
Affected Products (CPE)CVE.org
A vulnerability was found in obgm libcoap 4.3.4. Rated high severity (CVSS 7.8), this vulnerability is low attack comple
An issue in `coap_pdu.c` in libcoap 4.3.4 allows attackers to cause undefined behavior via a sequence of messages leadin
Buffer Overflow vulnerability in coap_send function in libcoap library 4.3.1-103-g52cfd56 fixed in 4.3.1-120-ge242200 al
libcoap 4.3.1 contains a buffer over-read via the function coap_parse_oscore_conf_mem at coap_oscore.c. Rated medium sev
Out-of-bounds read in libcoap's OSCORE CBOR parsing can escalate to heap buffer overflow, enabling remote unauthenticate
Availability loss and potential remote code execution in libcoap (versions up to and including 4.3.5, before commit 30db
A memory disclosure vulnerability exists in libcoap's OSCORE configuration parser in libcoap before release-4.3.5-patche
Null pointer dereference in coap_dtls_info_callback() in OISM libcoap 4.3.5 allows remote attackers to cause a denial of
NULL pointer dereference in coap_dtls_generate_cookie() in src/coap_openssl.c in OISM libcoap 4.3.5 allows remote attack
Array index error in tls_verify_call_back() in src/coap_openssl.c in OISM libcoap 4.3.5 allows remote attackers to cause
NULL pointer dereference in coap_dtls_generate_cookie() in src/coap_openssl.c in OISM libcoap 4.3.5 allows remote attack
NULL pointer dereference in coap_dtls_generate_cookie() in src/coap_openssl.c in OISM libcoap 4.3.5 allows remote attack
Same weakness CWE-476 – NULL Pointer Dereference
View allSame technique Denial Of Service
View allVendor StatusVendor
SUSE
Severity: Medium| Product | Status |
|---|---|
| openSUSE Tumbleweed | Fixed |
GitHub PoC
Exploit-DB