CVE-2019-17211 — An integer overflow was discovered in the CoAP library in Arm Mbed OS 5

An integer overflow was discovered in the CoAP library in Arm Mbed OS 5.14.0. The function sn_coap_builder_calc_needed_packet_data_size_2() is used to calculate the required memory for the CoAP message from the sn_coap_hdr_s data structure. Both returned_byte_count and src_coap_m

01What is this vulnerability?

An integer overflow was discovered in the CoAP library in Arm Mbed OS 5.14.0. The function sn_coap_builder_calc_needed_packet_data_size_2() is used to calculate the required memory for the CoAP message from the sn_coap_hdr_s data structure. Both returned_byte_count and src_coap_msg_ptr->payload_len are of type uint16_t. When added together, the result returned_byte_count can wrap around the…

02Affected products

Vendor	Product	Versions
n	a / n/a	n/a

03Active exploitation status

Not currently listed on the CISA Known Exploited Vulnerabilities (KEV) catalog. EPSS is the best forward-looking signal — see the EPSS row above.

04Recommended remediation

• Patch to a fixed version listed in the vendor advisory (see references below).
• Mitigate with WAF rules, network egress filters, or feature flags where the patch is not yet available.
• Hunt historical logs for exploitation indicators — see Detection signatures below.

05Technical details

For the full vendor write-up, exploit chains, and reference implementations, see the references list in section 09.

06Detection signatures

Ask SARA in chat to draft a starting detection for this CVE in your stack of choice.

07Related CVEs

No directly-cited follow-up CVEs in the KB record for this advisory. The references list in section 09 carries the vendor cross-references.

08Timeline

• Published: 2019-11-05T15:06:40.000Z
• Last modified: 2024-08-05T01:33:17.231Z

09References

• github.com — https://github.com/ARMmbed/mbed-os/blob/d0686fd30b4d3d02efdc7e4d0fbf0dfe173543b6…
• github.com — https://github.com/ARMmbed/mbed-os/blob/d0686fd30b4d3d02efdc7e4d0fbf0dfe173543b6…
• github.com — https://github.com/ARMmbed/mbed-os/blob/d0686fd30b4d3d02efdc7e4d0fbf0dfe173543b6…
• github.com — https://github.com/ARMmbed/mbed-os/blob/d0686fd30b4d3d02efdc7e4d0fbf0dfe173543b6…
• github.com — https://github.com/ARMmbed/mbed-os/blob/d0686fd30b4d3d02efdc7e4d0fbf0dfe173543b6…
• github.com — https://github.com/ARMmbed/mbed-os/blob/d0686fd30b4d3d02efdc7e4d0fbf0dfe173543b6…
• github.com — https://github.com/ARMmbed/mbed-os/blob/d0686fd30b4d3d02efdc7e4d0fbf0dfe173543b6…
• github.com — https://github.com/ARMmbed/mbed-os/issues/11804