CVE-2021-26544Network attack vector

Session hijacking via unescaped session names

Published Feb 20, 2021 · Updated Feb 13, 2025

Stored cross-site scripting in Apache Livy 0.7.0-incubating allows remote authenticated users to hijack another user's session. The all-sessions UI passes attacker-controlled session.name values directly to tdWrap and appends the resulting string as HTML without escaping. A victim must open the shared sessions page; injected script can read session logs and results and submit jobs with the victim's privileges.

CVSS severity5.4
Medium
EPSS probability2.82%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stored cross-site scripting in Apache Livy 0.7.0-incubating allows remote authenticated users to hijack another user's session. The all-sessions UI passes attacker-controlled session.name values directly to tdWrap and appends the resulting string as HTML without escaping. A victim must open the shared sessions page; injected script can read session logs and results and submit jobs with the victim's privileges.

The record

CVE
CVE-2021-26544
Published
Feb 20, 2021
Updated
Feb 13, 2025
Vendor
The Apache Software Foundation
Product
Apache Livy
Classifications
CWE-79, T1059.007
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Feb 20, 2021CVE publishedPublication date reported by the CVE source.
  2. Feb 13, 2025Record 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=Apache Livy (Incubating) 0.7.0-incubating

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

The Apache Software Foundation · Apache Livyversion=Apache Livy (Incubating) 0.7.0-incubating

Published CVSS scores

5.4NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
3.5NVDAV:N/AC:M/Au:S/C:N/I:P/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.

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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1059.007JavaScript/JScript

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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