CVE-2021-22887Known exploitation

Firmware compromise via missing BIOS write protection

Published Mar 16, 2021 · Updated Aug 3, 2024

Missing BIOS write protection in Pulse Secure PSA5000 and PSA7000 appliances allows local users with high privileges to modify firmware. The BIOS leaves SPI flash write protections unlocked, allowing privileged code to rewrite or erase the firmware region. The device must already be compromised, and successful abuse can install persistent firmware code or render the appliance unbootable.

CVSS severity2.3
Low
EPSS probability0.25%
Next 30 days · Sep 16, 2026
Known exploitationReported
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Missing BIOS write protection in Pulse Secure PSA5000 and PSA7000 appliances allows local users with high privileges to modify firmware. The BIOS leaves SPI flash write protections unlocked, allowing privileged code to rewrite or erase the firmware region. The device must already be compromised, and successful abuse can install persistent firmware code or render the appliance unbootable.

The record

CVE
CVE-2021-22887
Published
Mar 16, 2021
Updated
Aug 3, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-506, T1542.001
Attack vector
local
Privileges
admin

Timeline

How it unfolded

  1. Mar 16, 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 vectorlocal
Required privilegesadmin

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

2.1NIST NVDAV:L/AC:L/Au:N/C:N/I:P/A:N
2.3NIST NVDCVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:L/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)
Vectorlocal
Privilegesadmin
Known exploitationReported
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-506Embedded Malicious Code
T1542.001System Firmware

Public exploit references

No public exploit references are available in this record.

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

Reported exploitation

Technologies

Your stack

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Your stack

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