CVE-2021-31802Public exploit

Root code execution via mismatched upload lengths

Published Apr 26, 2021 · Updated Aug 3, 2024

Heap-based buffer overflow in NETGEAR R7000 firmware 1.0.11.116 and earlier allows remote attackers to execute code as root via crafted HTTP uploads. The backup.cgi handler allocates a heap buffer from the attacker-controlled Content-Length value but copies the request body using its independently derived, larger length. No authentication or user interaction is required from the local network; internet reachability requires Remote Management, which is disabled by default.

CVSS severity9.6
Critical
EPSS probability14.18%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Heap-based buffer overflow in NETGEAR R7000 firmware 1.0.11.116 and earlier allows remote attackers to execute code as root via crafted HTTP uploads. The backup.cgi handler allocates a heap buffer from the attacker-controlled Content-Length value but copies the request body using its independently derived, larger length. No authentication or user interaction is required from the local network; internet reachability requires Remote Management, which is disabled by default.

The record

CVE
CVE-2021-31802
Published
Apr 26, 2021
Updated
Aug 3, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-787, T1210
Attack vector
adjacent
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 26, 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 vectoradjacent
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

8.8NIST NVDCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
8.3NIST NVDAV:A/AC:L/Au:N/C:C/I:C/A:C
9.6NETGEARCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

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)
Vectoradjacent
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-787Out-of-bounds Write
T1210Exploitation of Remote Services

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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