CVE-2021-31662Public exploitNetwork attack vector

Sensitive-memory disclosure via unchecked URI lookahead

Published Jun 18, 2021 · Updated Aug 3, 2024

Out-of-bounds read in RIOT-OS 2021.01 allows remote attackers to read sensitive memory by supplying a short URI to the URI parser. In sys/uri_parser/uri_parser.c, _consume_scheme reads p[1] and p[2] while checking for :// without first verifying that those bytes lie within the caller-supplied buffer. No authentication or user interaction is required, but exposure depends on an application passing attacker-controlled URI bytes to uri_parser_process.

CVSS severity7.5
High
EPSS probability1.34%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Out-of-bounds read in RIOT-OS 2021.01 allows remote attackers to read sensitive memory by supplying a short URI to the URI parser. In sys/uri_parser/uri_parser.c, _consume_scheme reads p[1] and p[2] while checking for :// without first verifying that those bytes lie within the caller-supplied buffer. No authentication or user interaction is required, but exposure depends on an application passing attacker-controlled URI bytes to uri_parser_process.

The record

CVE
CVE-2021-31662
Published
Jun 18, 2021
Updated
Aug 3, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-120
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 18, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

5.0NIST NVDAV:N/AC:L/Au:N/C:P/I:N/A:N
7.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-120Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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