CVE-2021-27256

CVSS V2 High 8.3 CVSS V3 High 8.8
Description
This vulnerability allows network-adjacent attackers to execute arbitrary code on affected installations of NETGEAR R7800 firmware version 1.0.2.76. Although authentication is required to exploit this vulnerability, the existing authentication mechanism can be bypassed. The specific flaw exists within the handling of the rc_service parameter provided to apply_save.cgi. The issue results from the lack of proper validation of a user-supplied string before using it to execute a system call. An attacker can leverage this vulnerability to execute code in the context of root. Was ZDI-CAN-12355.
Overview
  • CVE ID
  • CVE-2021-27256
  • Assigner
  • zdi-disclosures@trendmicro.com
  • Vulnerability Status
  • Analyzed
  • Published Version
  • 2021-03-05T20:15:12
  • Last Modified Date
  • 2021-03-16T19:35:09
Weakness Enumerations
CWE URL
CWE-78 http://cwe.mitre.org/data/definitions/78.html
CPE Configuration (Product)
CPE Vulnerable Operator Version Start Version End
AND
cpe:2.3:o:netgear:br200_firmware:*:*:*:*:*:*:*:* 1 OR 5.10.0.5
cpe:2.3:h:netgear:br200:-:*:*:*:*:*:*:* 0 OR
AND
cpe:2.3:o:netgear:br500_firmware:*:*:*:*:*:*:*:* 1 OR 5.10.0.5
cpe:2.3:h:netgear:br500:-:*:*:*:*:*:*:* 0 OR
AND
cpe:2.3:o:netgear:d7800_firmware:*:*:*:*:*:*:*:* 1 OR 1.0.1.60
cpe:2.3:h:netgear:d7800:-:*:*:*:*:*:*:* 0 OR
AND
cpe:2.3:o:netgear:ex6100v2_firmware:*:*:*:*:*:*:*:* 1 OR 1.0.1.98
cpe:2.3:h:netgear:ex6100v2:-:*:*:*:*:*:*:* 0 OR
AND
cpe:2.3:o:netgear:ex6150v2_firmware:*:*:*:*:*:*:*:* 1 OR 1.0.1.98
cpe:2.3:h:netgear:ex6150v2:-:*:*:*:*:*:*:* 0 OR
AND
cpe:2.3:o:netgear:ex6250_firmware:*:*:*:*:*:*:*:* 1 OR 1.0.0.134
cpe:2.3:h:netgear:ex6250:-:*:*:*:*:*:*:* 0 OR
AND
cpe:2.3:o:netgear:ex6400_firmware:*:*:*:*:*:*:*:* 1 OR 1.0.2.158
cpe:2.3:h:netgear:ex6400:-:*:*:*:*:*:*:* 0 OR
AND
cpe:2.3:o:netgear:ex6400v2_firmware:*:*:*:*:*:*:*:* 1 OR 1.0.0.134
cpe:2.3:h:netgear:ex6400v2:-:*:*:*:*:*:*:* 0 OR
AND
cpe:2.3:o:netgear:ex6410_firmware:*:*:*:*:*:*:*:* 1 OR 1.0.0.134
cpe:2.3:h:netgear:ex6410:-:*:*:*:*:*:*:* 0 OR
AND
cpe:2.3:o:netgear:ex6420_firmware:*:*:*:*:*:*:*:* 1 OR 1.0.0.134
cpe:2.3:h:netgear:ex6420:-:*:*:*:*:*:*:* 0 OR
AND
cpe:2.3:o:netgear:ex7300_firmware:*:*:*:*:*:*:*:* 1 OR 1.0.2.158
cpe:2.3:h:netgear:ex7300:-:*:*:*:*:*:*:* 0 OR
AND
cpe:2.3:o:netgear:ex7300v2_firmware:*:*:*:*:*:*:*:* 1 OR 1.0.0.134
cpe:2.3:h:netgear:ex7300v2:-:*:*:*:*:*:*:* 0 OR
AND
cpe:2.3:o:netgear:ex7320_firmware:*:*:*:*:*:*:*:* 1 OR 1.0.0.134
cpe:2.3:h:netgear:ex7320:-:*:*:*:*:*:*:* 0 OR
AND
cpe:2.3:o:netgear:ex7700_firmware:*:*:*:*:*:*:*:* 1 OR 1.0.0.216
cpe:2.3:h:netgear:ex7700:-:*:*:*:*:*:*:* 0 OR
AND
cpe:2.3:o:netgear:ex8000_firmware:*:*:*:*:*:*:*:* 1 OR 1.0.1.232
cpe:2.3:h:netgear:ex8000:-:*:*:*:*:*:*:* 0 OR
AND
cpe:2.3:o:netgear:lbr20_firmware:*:*:*:*:*:*:*:* 1 OR 2.6.3.50
cpe:2.3:h:netgear:lbr20:-:*:*:*:*:*:*:* 0 OR
AND
cpe:2.3:o:netgear:r7800_firmware:*:*:*:*:*:*:*:* 1 OR 1.0.2.80
cpe:2.3:h:netgear:r7800:-:*:*:*:*:*:*:* 0 OR
AND
cpe:2.3:o:netgear:r8900_firmware:*:*:*:*:*:*:*:* 1 OR 1.0.5.28
cpe:2.3:h:netgear:r8900:-:*:*:*:*:*:*:* 0 OR
AND
cpe:2.3:o:netgear:r9000_firmware:*:*:*:*:*:*:*:* 1 OR 1.0.5.28
cpe:2.3:h:netgear:r9000:-:*:*:*:*:*:*:* 0 OR
AND
cpe:2.3:o:netgear:rbk12_firmware:*:*:*:*:*:*:*:* 1 OR 2.7.2.104
cpe:2.3:h:netgear:rbk12:-:*:*:*:*:*:*:* 0 OR
AND
cpe:2.3:o:netgear:rbk13_firmware:*:*:*:*:*:*:*:* 1 OR 2.7.2.104
cpe:2.3:h:netgear:rbk13:-:*:*:*:*:*:*:* 0 OR
AND
cpe:2.3:o:netgear:rbk14_firmware:*:*:*:*:*:*:*:* 1 OR 2.7.2.104
cpe:2.3:h:netgear:rbk14:-:*:*:*:*:*:*:* 0 OR
AND
cpe:2.3:o:netgear:rbk15_firmware:*:*:*:*:*:*:*:* 1 OR 2.7.2.104
cpe:2.3:h:netgear:rbk15:-:*:*:*:*:*:*:* 0 OR
AND
cpe:2.3:o:netgear:rbk20_firmware:*:*:*:*:*:*:*:* 1 OR 2.6.2.104
cpe:2.3:h:netgear:rbk20:-:*:*:*:*:*:*:* 0 OR
AND
cpe:2.3:o:netgear:rbk23_firmware:*:*:*:*:*:*:*:* 1 OR 2.7.2.104
cpe:2.3:h:netgear:rbk23:-:*:*:*:*:*:*:* 0 OR
AND
cpe:2.3:o:netgear:rbk40_firmware:*:*:*:*:*:*:*:* 1 OR 2.6.2.104
cpe:2.3:h:netgear:rbk40:-:*:*:*:*:*:*:* 0 OR
AND
cpe:2.3:o:netgear:rbk43_firmware:*:*:*:*:*:*:*:* 1 OR 2.6.2.104
cpe:2.3:h:netgear:rbk43:-:*:*:*:*:*:*:* 0 OR
AND
cpe:2.3:o:netgear:rbk43s_firmware:*:*:*:*:*:*:*:* 1 OR 2.6.2.104
cpe:2.3:h:netgear:rbk43s:-:*:*:*:*:*:*:* 0 OR
AND
cpe:2.3:o:netgear:rbk44_firmware:*:*:*:*:*:*:*:* 1 OR 2.6.2.104
cpe:2.3:h:netgear:rbk44:-:*:*:*:*:*:*:* 0 OR
AND
cpe:2.3:o:netgear:rbk50_firmware:*:*:*:*:*:*:*:* 1 OR 2.7.2.104
cpe:2.3:h:netgear:rbk50:-:*:*:*:*:*:*:* 0 OR
AND
cpe:2.3:o:netgear:rbk53_firmware:*:*:*:*:*:*:*:* 1 OR 2.7.2.104
cpe:2.3:h:netgear:rbk53:-:*:*:*:*:*:*:* 0 OR
AND
cpe:2.3:o:netgear:rbr10_firmware:*:*:*:*:*:*:*:* 1 OR 2.6.2.104
cpe:2.3:h:netgear:rbr10:-:*:*:*:*:*:*:* 0 OR
AND
cpe:2.3:o:netgear:rbr20_firmware:*:*:*:*:*:*:*:* 1 OR 2.6.2.104
cpe:2.3:h:netgear:rbr20:-:*:*:*:*:*:*:* 0 OR
AND
cpe:2.3:o:netgear:rbr40_firmware:*:*:*:*:*:*:*:* 1 OR 2.6.2.104
cpe:2.3:h:netgear:rbr40:-:*:*:*:*:*:*:* 0 OR
AND
cpe:2.3:o:netgear:rbr50_firmware:*:*:*:*:*:*:*:* 1 OR 2.7.2.104
cpe:2.3:h:netgear:rbr50:-:*:*:*:*:*:*:* 0 OR
AND
cpe:2.3:o:netgear:rbs10_firmware:*:*:*:*:*:*:*:* 1 OR 2.6.2.104
cpe:2.3:h:netgear:rbs10:-:*:*:*:*:*:*:* 0 OR
AND
cpe:2.3:o:netgear:rbs20_firmware:*:*:*:*:*:*:*:* 1 OR 2.6.2.104
cpe:2.3:h:netgear:rbs20:-:*:*:*:*:*:*:* 0 OR
AND
cpe:2.3:o:netgear:rbs40_firmware:*:*:*:*:*:*:*:* 1 OR 2.6.2.104
cpe:2.3:h:netgear:rbs40:-:*:*:*:*:*:*:* 0 OR
AND
cpe:2.3:o:netgear:rbs50_firmware:*:*:*:*:*:*:*:* 1 OR 2.7.2.104
cpe:2.3:h:netgear:rbs50:-:*:*:*:*:*:*:* 0 OR
AND
cpe:2.3:o:netgear:rbs50y_firmware:*:*:*:*:*:*:*:* 1 OR 2.6.2.104
cpe:2.3:h:netgear:rbs50y:-:*:*:*:*:*:*:* 0 OR
AND
cpe:2.3:o:netgear:xr450_firmware:*:*:*:*:*:*:*:* 1 OR 2.3.2.114
cpe:2.3:h:netgear:xr450:-:*:*:*:*:*:*:* 0 OR
AND
cpe:2.3:o:netgear:xr500_firmware:*:*:*:*:*:*:*:* 1 OR 2.3.2.114
cpe:2.3:h:netgear:xr500:-:*:*:*:*:*:*:* 0 OR
AND
cpe:2.3:o:netgear:xr700_firmware:*:*:*:*:*:*:*:* 1 OR 1.0.1.38
cpe:2.3:h:netgear:xr700:-:*:*:*:*:*:*:* 0 OR
CVSS Version 2
  • Version
  • 2.0
  • Vector String
  • AV:A/AC:L/Au:N/C:C/I:C/A:C
  • Access Vector
  • ADJACENT_NETWORK
  • Access Compatibility
  • LOW
  • Authentication
  • NONE
  • Confidentiality Impact
  • COMPLETE
  • Integrity Impact
  • COMPLETE
  • Availability Impact
  • COMPLETE
  • Base Score
  • 8.3
  • Severity
  • HIGH
  • Exploitability Score
  • 6.5
  • Impact Score
  • 10
CVSS Version 3
  • Version
  • 3.1
  • Vector String
  • CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
  • Attack Vector
  • ADJACENT_NETWORK
  • Attack Compatibility
  • LOW
  • Privileges Required
  • NONE
  • User Interaction
  • NONE
  • Scope
  • UNCHANGED
  • Confidentiality Impact
  • HIGH
  • Availability Impact
  • HIGH
  • Base Score
  • 8.8
  • Base Severity
  • HIGH
  • Exploitability Score
  • 2.8
  • Impact Score
  • 5.9
References
Reference URL Reference Tags
https://www.zerodayinitiative.com/advisories/ZDI-21-262/ Third Party Advisory VDB Entry
https://kb.netgear.com/000062883/Security-Advisory-for-Multiple-Vulnerabilities-on-Some-Routers-Satellites-and-Extenders Patch Vendor Advisory
Sources
Source Name Source URL
NIST https://nvd.nist.gov/vuln/detail/CVE-2021-27256
MITRE https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-27256
History
Created Old Value New Value Data Type Notes
2022-05-10 07:19:40 Added to TrackCVE
2022-12-05 23:14:07 2021-03-05T20:15Z 2021-03-05T20:15:12 CVE Published Date updated
2022-12-05 23:14:07 2021-03-16T19:35:09 CVE Modified Date updated
2022-12-05 23:14:07 Analyzed Vulnerability Status updated