CVE-2021-42551Public exploitNetwork attack vector

Script execution via unencoded Wikipedia search term

Published Jan 14, 2022 · Updated Aug 4, 2024

Reflected XSS in AlCoda NetBiblio WebOPAC before 4.0.0.320 and 4.0.0.329 through 4.0.0.334 allows remote attackers to execute script via search. The Wikipedia enrichment module embeds the searchTerm request value in a single-quoted JavaScript SearchTerm value without encoding; later builds escape quotes but accept a backslash that cancels the escape. Exploitation requires the Wikipedia module to be enabled and a victim to follow a crafted link, after which attacker-supplied script runs in that victim's WebOPAC session.

CVSS severity6.1
Medium
EPSS probability2.67%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Reflected XSS in AlCoda NetBiblio WebOPAC before 4.0.0.320 and 4.0.0.329 through 4.0.0.334 allows remote attackers to execute script via search. The Wikipedia enrichment module embeds the searchTerm request value in a single-quoted JavaScript SearchTerm value without encoding; later builds escape quotes but accept a backslash that cancels the escape. Exploitation requires the Wikipedia module to be enabled and a victim to follow a crafted link, after which attacker-supplied script runs in that victim's WebOPAC session.

The record

CVE
CVE-2021-42551
Published
Jan 14, 2022
Updated
Aug 4, 2024
Vendor
AlCoda GmbH
Product
NetBiblio WebOPAC
Classifications
CWE-79, T1204.001
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 14, 2022CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 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=next of 4.0.0.328 <unspecified
  2. Affected versionversion=unspecified <4.0.0.320

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

AlCoda GmbH · NetBiblio WebOPACversion=next of 4.0.0.328 <unspecified; version=unspecified <4.0.0.320

Published CVSS scores

4.3NIST NVDAV:N/AC:M/Au:N/C:N/I:P/A:N
6.1Switzerland Government Common Vulnerability ProgramCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/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)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1204.001User Execution: Malicious Link

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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