Eclipse tinyDTLS OOB read in DTLS handshake may cause DoS
CVE-2026-9267 Published on June 29, 2026
Eclipse tinydtls before commit b3efd41ad111a4920f599f51ffa4f5e9f1e72221 contains an out-of-bounds read vulnerability in the check_server_certificate() function that allows unauthenticated attackers to trigger reads beyond valid buffer boundaries by crafting a Certificate handshake message with a specific fragment_length value. Attackers can exploit missing buffer length validation before uint24 reads, memcmp, and memcpy operations during DTLS epoch 0 on both client and server paths to cause denial of service on memory-constrained devices.
Weakness Type
Out-of-bounds Read
The software reads data past the end, or before the beginning, of the intended buffer. Typically, this can allow attackers to read sensitive information from other memory locations or cause a crash. A crash can occur when the code reads a variable amount of data and assumes that a sentinel exists to stop the read operation, such as a NUL in a string. The expected sentinel might not be located in the out-of-bounds memory, causing excessive data to be read, leading to a segmentation fault or a buffer overflow. The software may modify an index or perform pointer arithmetic that references a memory location that is outside of the boundaries of the buffer. A subsequent read operation then produces undefined or unexpected results.
Affected Versions
Eclipse Foundation Eclipse tinydtls:- Before b3efd41ad111a4920f599f51ffa4f5e9f1e72221 is affected.