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.
Scores
CVSS v3
4.3
EPSS
0.0012
EPSS Percentile
30.5%
Attack Vector
NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L
CISA SSVC
Vulnrichment
Exploitation
none
Automatable
no
Technical Impact
partial
Details
CWE
CWE-129
Status
published
Products (1)
libcoap/libcoap
4.3.5
Published
Nov 24, 2025
Tracked Since
Feb 18, 2026