CVE-2026-29856Public exploitNetwork attack vector

Service interruption via VirtualHost regex backtracking

Published Mar 18, 2026 · Updated Mar 18, 2026

Regular expression denial of service in aaPanel 7.57.0 allows remote attackers to hang VirtualHost parsing via crafted configuration input. Patterns in domain_tool.py and ssl.py place ambiguous repetition before nested digit quantifiers, causing catastrophic backtracking on long repetitive strings. Unauthenticated network access suffices; exploitation consumes CPU or triggers parser timeouts, interrupting configuration processing.

CVSS severity7.5
High
EPSS probability0.34%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Regular expression denial of service in aaPanel 7.57.0 allows remote attackers to hang VirtualHost parsing via crafted configuration input. Patterns in domain_tool.py and ssl.py place ambiguous repetition before nested digit quantifiers, causing catastrophic backtracking on long repetitive strings. Unauthenticated network access suffices; exploitation consumes CPU or triggers parser timeouts, interrupting configuration processing.

The record

CVE
CVE-2026-29856
Published
Mar 18, 2026
Updated
Mar 18, 2026
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-400, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 18, 2026CVE publishedPublication date reported by the CVE source.
  2. Mar 18, 2026Record 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 vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

7.5CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/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.

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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-400Uncontrolled Resource Consumption
T1499.004Application or System Exploitation

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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