Buffer overflows in RIOT
RIOT is a real-time multi-threading operating system that supports a range of devices that are typically 8-bit, 16-bit and 32-bit microcontrollers. The size check in the `gcoap_dns_server_proxy_get()` function contains a small typo that may lead to a buffer overflow in the subsequent `strcpy()`. In detail, the length of the `_uri` string is checked instead of the length of the `_proxy` string. The `_gcoap_forward_proxy_copy_options()` function does not implement an explicit size check before copying data to the `cep->req_etag` buffer that is `COAP_ETAG_LENGTH_MAX` bytes long. If an attacker can craft input so that `optlen` becomes larger than `COAP_ETAG_LENGTH_MAX`, they can cause a buffer overflow. If the input above is attacker-controlled and crosses a security boundary, the impact of the buffer overflow vulnerabilities could range from denial of service to arbitrary code execution. This issue has yet to be patched. Users are advised to add manual bounds checking.
- Published
- May 1, 2024
- Updated
- Jun 17, 2026
- EPSS
- 1.5% · 74th percentile
- CWE
- CWE-120
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Report tools
Action score
36
Monitor
Low priority for now.
- CVSS
- 36 / 40 · 9.0 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 0 / 30 · 1.5%
CISA SSVC decision
- Exploitation
- proof of concept
- Automatable
- yes
- Technical impact
- total
Vulnrichment: CISA's decision-tree inputs.
CNA vs NVD score
- NVD
- 9.0
- CNA · GitHub_M
- 9.8
- 0.8 point gap
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.
Noroxi analysis
No Noroxi analysis for this record yet
We don't hand-write analysis for the hundreds of thousands of vulnerabilities in the database; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.
We use this product, ask for helpAffected systems
| Vendor | Product | CPE |
|---|---|---|
| riot-os | riot | cpe:2.3:o:riot-os:riot |
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- riot-os riotup to 2024.01 inclusive
Versions reported by the vendor
Affected version ranges reported by the assigning authority (GitHub_M). Independent of NVD's CPE analysis and usually ahead of it.
RIOT-OS RIOT
- <= 2023.10affected
Same product
riot-os: all recordsOther highest-scoring records for the same primary product.
- CVE-2021-27427RIOT OS Integer Overflow or Wraparound40Plan
- CVE-2026-27703RIOT has an Out-of-Bounds Write in nanoCoAP Handler39Monitor
- CVE-2023-33975RIOT-OS vulnerable to Out of Bounds Write in _rbuf_add39Monitor
- CVE-2023-24823RIOT-OS vulnerable to Packet Type Confusion during IPHC send39Monitor
- CVE-2023-24819RIOT-OS vulnerable to Buffer Overflow during IPHC receive39Monitor
- CVE-2021-27698RIOT-OS 2021.01 contains a buffer overflow vulnerability in /sys/net/gnrc/routing/rpl/gnrc_rpl_control_messages.c through the _parse_options39Monitor
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
No fix version is recorded for this entry. Check the references for vendor advisories.
Exploit status
No known public exploit
No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.
Research context
For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.
Timeline
From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.
No dated events beyond publication.
FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).
Patch and commit links
Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.
No commit or PR link among the references.
Credits
All researchersFinders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.
No credits in the CNA record.
Variant candidates
Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.
- CVE-2024-312250 days apartLack of size check and buffer overflow in RIOT36Monitor
- CVE-2024-320180 days apartIneffective size check due to assert() and buffer overflow in RIOT36Monitor
- CVE-2025-53888443 days apartRIOT-OS has an ineffective size check that can lead to buffer overflow in link layer address filter /sys/net/link_layer/l2filter/l2filter.c26Monitor
Chain candidates
An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.
—
Bug bounty scope
No known public program.
Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).
Technical details
Attack conditions
- Anyone who can reach it over the internet can trigger it.
- No account or password is required.
- No user action is required.
- Special conditions such as timing or configuration are required.
If successful
- Confidentiality
- high · data can be read
- Integrity
- high · data or configuration can be modified
- Availability
- high · the service can be disrupted
Impact can extend beyond the vulnerable component (scope changes).
- Attack vector
- Network
- Attack complexity
- High
- Privileges required
- None
- User interaction
- None
- Scope
- Changed
- Confidentiality impact
- High
- Integrity impact
- High
- Availability impact
- High
Weakness class (CWE)
CWE-120 · Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')CVSS vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H
nvd-primary
Root cause
When data is copied, the source length is not compared with the size of the destination buffer. Excess data overwrites adjacent memory.
The bug in code
The whole CWE-120 classA representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.
Vulnerable
char buf[256];memcpy(buf, pkt->data, pkt->len);Fixed
char buf[256];if (pkt->len > sizeof(buf)) { return -EINVAL;}memcpy(buf, pkt->data, pkt->len);Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
Attack patterns (CAPEC)
- Buffer Overflow via Environment VariablesCAPEC-10likelihood: High · High
- Overflow BuffersCAPEC-100likelihood: High · Very High
- Client-side Injection-induced Buffer OverflowCAPEC-14likelihood: Medium · High
- Filter Failure through Buffer OverflowCAPEC-24likelihood: High · High
- MIME ConversionCAPEC-42likelihood: High · High
- Overflow Binary Resource FileCAPEC-44likelihood: High · Very High
- Buffer Overflow via Symbolic LinksCAPEC-45likelihood: High · High
- Overflow Variables and TagsCAPEC-46likelihood: High · High
ATT&CK techniques
—
Change log
No changes recorded on tracked fields yet. Score, KEV, exploit maturity and fix status changes appear here.
References
- seclists.org/fulldisclosure/2024/May/7
- www.openwall.com/lists/oss-security/2024/05/07/3
- github.com/RIOT-OS/RIOT/blob/master/sys/net/application_layer/gcoap/dns.c#L319-L325
- github.com/RIOT-OS/RIOT/blob/master/sys/net/application_layer/gcoap/forward_proxy.c#L352
Vendor advisories and official records. Exploit/PoC links are deliberately left out.