CVE-2020-12886
CVE-2020-12886 is a critical-severity vulnerability in Arm Mbed Os with a CVSS 3.x base score of 9.1. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-125.
Key facts
- Severity: Critical (CVSS 3.x base score 9.1)
- CVSS v2: 6.4
- EPSS exploit prediction: 1% (68th percentile)
- Actively exploited: Not listed in CISA KEV
- Weakness: CWE-125
- Affected product: Arm Mbed Os
- Published:
- Last modified:
Description
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.
Frequently asked questions
- What is CVE-2020-12886?
- 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.
- How severe is CVE-2020-12886?
- CVE-2020-12886 has a CVSS 3.x base score of 9.1, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability high.
- Is CVE-2020-12886 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (68th percentile), an estimate of the probability of exploitation in the next 30 days.
- What products are affected by CVE-2020-12886?
- CVE-2020-12886 affects Arm Mbed Os. See the affected-products list for the exact vulnerable versions.
- How do I fix CVE-2020-12886?
- Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
- When was CVE-2020-12886 published?
- CVE-2020-12886 was published on 2020-06-18 and last updated on 2026-06-17.
References
Affected products (1)
- cpe:2.3:o:arm:mbed_os:5.15.3:*:*:*:*:*:*:*
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