CVE-2021-31987Network attack vector

Local resource access via recipient-test validation bypass

Published Oct 5, 2021 · Updated Nov 8, 2024

SSRF in Axis Communications AB AXIS OS 5.51 and later allows remote authenticated users to reach blocked services through recipient tests. HTTP, HTTPS, email, and TCP recipient tests rely on bypassable blocklists; HTTP also accepts non-HTTP schemes, and HTTPS applies ineffective HTTP checks. Exploitation requires network access plus device-administrator privileges, or a logged-in administrator induced to visit a crafted webpage, and can expose localhost services or local files.

CVSS severity7.5
High
EPSS probability0.89%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

SSRF in Axis Communications AB AXIS OS 5.51 and later allows remote authenticated users to reach blocked services through recipient tests. HTTP, HTTPS, email, and TCP recipient tests rely on bypassable blocklists; HTTP also accepts non-HTTP schemes, and HTTPS applies ineffective HTTP checks. Exploitation requires network access plus device-administrator privileges, or a logged-in administrator induced to visit a crafted webpage, and can expose localhost services or local files.

The record

CVE
CVE-2021-31987
Published
Oct 5, 2021
Updated
Nov 8, 2024
Vendor
Axis Communications AB
Product
AXIS OS
Classifications
CWE-1286, T1190
Attack vector
network
Privileges
admin

Timeline

How it unfolded

  1. Oct 5, 2021CVE publishedPublication date reported by the CVE source.
  2. Nov 8, 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?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=AXIS OS 5.51 or later

What conditions does exploitation require?

Attack vectornetwork
Required privilegesadmin

What is affected?

Axis Communications AB · AXIS OSversion=AXIS OS 5.51 or later

Published CVSS scores

5.1NIST NVDAV:N/AC:H/Au:N/C:P/I:P/A:P
7.5NIST NVDCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

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
Privilegesadmin
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-1286Improper Validation of Syntactic Correctness of Input
T1190Exploit Public-Facing Application

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.

Technologies

Your stack

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Your stack

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