CVE-2020-3244Network attack vector

Traffic classification bypass via malformed HTTP request

Published Jun 18, 2020 · Updated Nov 15, 2024

Improper input validation in Cisco ASR 5000 Series Software before 21.18.0 allows remote attackers to bypass ECS traffic rules. ECS insufficiently validates malformed HTTP requests when a configured rule matches the CONNECT method, allowing traffic to evade classification. Exposure requires an ECS rule configured for CONNECT; successful requests can avoid traffic-consumption charging without affecting confidentiality or availability.

CVSS severity5.3
Medium
EPSS probability1.01%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper input validation in Cisco ASR 5000 Series Software before 21.18.0 allows remote attackers to bypass ECS traffic rules. ECS insufficiently validates malformed HTTP requests when a configured rule matches the CONNECT method, allowing traffic to evade classification. Exposure requires an ECS rule configured for CONNECT; successful requests can avoid traffic-consumption charging without affecting confidentiality or availability.

The record

CVE
CVE-2020-3244
Published
Jun 18, 2020
Updated
Nov 15, 2024
Vendor
ClamAV
Product
Cisco ASR 5000 Series Software
Classifications
CWE-20
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 18, 2020CVE publishedPublication date reported by the CVE source.
  2. Nov 15, 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?

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  1. Affected versionversion=n/a

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

ClamAV · Cisco ASR 5000 Series Softwareversion=n/a

Published CVSS scores

5.3CiscoCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N/E:X/RL:X/RC:X
5.3NISTCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
5.0NISTAV:N/AC:L/Au:N/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.

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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 exploitUnconfirmed

Weakness, pattern, technique

CWE-20Improper Input Validation

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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