CVE-2020-12886 json
A buffer over-read was discovered in the CoAP library in Arm Mbed OS 5.15.3.
published 2020-06-18 6 y ago modified 2026-06-17 4 mo ago also EUVD-2020-5167
- cvss
- 9.1
- version 3.1, NVD
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 1.4%
- EPSS 1.4% chance of exploitation in 30 days, percentile 71%
- public exploits
- 0
- none known
Summary
A buffer over-read was discovered in the CoAP library in Arm Mbed OS 5.15.3. The CoAP parser is responsible for parsing received CoAP packets. The function sn_coap_parser_options_parse() parses the CoAP packet header starting from the message token. The length of the token in the received message is provided in the first byte parsed by the sn_coap_parser_options_parse() function. The length encoded in the message is not validated against the actual input buffer length before accessing the token. As a result, memory access outside of the intended boundary of the buffer may occur.
Patch / fix
- github.com/ARMmbed/mbed-coap#116 pull request
Exploit prediction
1.35% chance of exploitation in the next 30 days, higher than 71% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| NVD | 3.1 | 9.1 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H |
| NVD | 2.0 | 6.4 | AV:N/AC:L/Au:N/C:P/I:N/A:P |
Classification
- Weakness
-
- CWE-125 Out-of-bounds Read
References
-
github.com
/ARMmbed/mbed-coap/pull/116
third-party-advisory
-
github.com
/ARMmbed/mbed-os/issues/12948
third-party-advisory
Sources
- CVE List CVE-2020-12886
- NVD CVE-2020-12886
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