CVE-2021-20411

User impersonation via unchanged login session identifier

Published Feb 12, 2021 · Updated Sep 16, 2024

Session fixation in IBM Security Verify Information Queue 1.0.6 and 1.0.7 allows attackers to impersonate users via reused session identifiers. The web server fails to replace an existing session identifier consistently when a new user logs in, allowing the prior identifier holder to commandeer the authenticated session. Exploitation requires a victim login using the retained identifier and grants access to data and actions available through that user's session.

CVSS severity7.5
High
EPSS probability0.45%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Session fixation in IBM Security Verify Information Queue 1.0.6 and 1.0.7 allows attackers to impersonate users via reused session identifiers. The web server fails to replace an existing session identifier consistently when a new user logs in, allowing the prior identifier holder to commandeer the authenticated session. Exploitation requires a victim login using the retained identifier and grants access to data and actions available through that user's session.

The record

CVE
CVE-2021-20411
Published
Feb 12, 2021
Updated
Sep 16, 2024
Vendor
IBM
Product
Security Verify Information Queue
Classifications
CWE-669, T1550.004
Attack vector
adjacent
Privileges
unauthenticated

Timeline

How it unfolded

  1. Feb 12, 2021CVE publishedPublication date reported by the CVE source.
  2. Sep 16, 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=1.0.6
  2. Affected versionversion=1.0.7

What conditions does exploitation require?

Attack vectoradjacent
Required privilegesunauthenticated

What is affected?

IBM · Security Verify Information Queueversion=1.0.6; version=1.0.7

Published CVSS scores

8.1NIST NVDCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
4.8NIST NVDAV:A/AC:L/Au:N/C:P/I:P/A:N
7.5IBM CorporationCVSS:3.0/AV:A/AC:H/PR:N/UI:R/S:C/C:H/I:H/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)
Vectoradjacent
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-669Incorrect Resource Transfer Between Spheres
T1550.004Web Session Cookie

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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