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CVE-2020-3299

Multiple Cisco Products SNORT HTTP Detection Engine File Policy Bypass Vulnerability

5.8 MediumFix available

CVE-2020-3299 is a medium vulnerability (CVSS 5.8) in Snort, published October 21, 2020. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 2.31%, the 83rd percentile. Fixed in snort 2.9.20-0+deb10u1.

Multiple Cisco products are affected by a vulnerability in the Snort detection engine that could allow an unauthenticated, remote attacker to bypass a configured File Policy for HTTP. The vulnerability is due to incorrect detection of modified HTTP packets used in chunked responses. An attacker could exploit this vulnerability by sending crafted HTTP packets through an affected device. A successful exploit could allow the attacker to bypass a configured File Policy for HTTP packets and deliver a malicious payload.

Attack profile

How easy it is to exploit

Attack vector
Network
Complexity
Low
Privileges needed
None
User interaction
None

What an attacker can affect

Confidentiality
None
Integrity
Low
Availability
None

Exploit likelihood

2.31%Up 1.8 points since Apr 14, 2021
90%50%10%1%

What each source reports

CVE List Score used 5.8

Multiple Cisco Products SNORT HTTP Detection Engine File Policy Bypass Vulnerability

Multiple Cisco products are affected by a vulnerability in the Snort detection engine that could allow an unauthenticated, remote attacker to bypass a configured File Policy for HTTP. The vulnerability is due to incorrect detection of modified HTTP packets used in chunked responses. An attacker could exploit this vulnerability by sending crafted HTTP packets through an affected device. A successful exploit could allow the attacker to bypass a configured File Policy for HTTP packets and deliver a malicious payload.

Record
CVE-2020-3299
CVSS 3.0
5.8 MediumCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N
Weakness
CWE-693
Updated
2026-11-02
EUVDEUVD-2020-24570 5.8

Multiple Cisco products are affected by a vulnerability in the Snort detection engine that could allow an unauthenticated, remote attacker to bypass a configured File Policy for HTTP. The vulnerability is due to incorrect detection of modified HTTP packets used in chunked responses. An attacker could exploit this vulnerability by sending crafted HTTP packets through an affected device. A successful exploit could allow the attacker to bypass a configured File Policy for HTTP packets and deliver a malicious payload.

Record
EUVD-2020-24570
CVSS 3.0
5.8 MediumCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N
Updated
2026-11-03
GitHub AdvisoriesGHSA-j2v5-cw33-rvx6 5.8

Multiple Cisco products are affected by a vulnerability in the Snort detection engine that could...

Multiple Cisco products are affected by a vulnerability in the Snort detection engine that could allow an unauthenticated, remote attacker to bypass a configured File Policy for HTTP. The vulnerability is due to incorrect detection of modified HTTP packets used in chunked responses. An attacker could exploit this vulnerability by sending crafted HTTP packets through an affected device. A successful exploit could allow the attacker to bypass a configured File Policy for HTTP packets and deliver a malicious payload.

Record
GHSA-j2v5-cw33-rvx6
CVSS 3.1
5.8 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N
Weakness
CWE-693
Updated
2026-11-02
NVD 5.8

Multiple Cisco products are affected by a vulnerability in the Snort detection engine that could allow an unauthenticated, remote attacker to bypass a configured File Policy for HTTP. The vulnerability is due to incorrect detection of modified HTTP packets used in chunked responses. An attacker could exploit this vulnerability by sending crafted HTTP packets through an affected device. A successful exploit could allow the attacker to bypass a configured File Policy for HTTP packets and deliver a malicious payload.

Record
CVE-2020-3299
CVSS 3.1
5.8 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N
CVSS 3.0
5.8 MediumCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N
CVSS 2.0
5.0 MediumAV:N/AC:L/Au:N/C:N/I:P/A:N
Weakness
CWE-693
Updated
2026-11-02
OSVUBUNTU-CVE-2020-3299 5.8

Multiple Cisco products are affected by a vulnerability in the Snort detection engine that could allow an unauthenticated, remote attacker to bypass a configured File Policy for HTTP. The vulnerability is due to incorrect detection of modified HTTP packets used in chunked responses. An attacker could exploit this vulnerability by sending crafted HTTP packets through an affected device. A successful exploit could allow the attacker to bypass a configured File Policy for HTTP packets and deliver a malicious payload.

Record
UBUNTU-CVE-2020-3299
CVSS 3.1
5.8 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N
CVSS 3.0
5.8 MediumCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N
Updated
2026-11-02
OSVMGASA-2023-0117 No score

Updated snort packages fix security vulnerability

Multiple Cisco products are affected by a vulnerability in the Snort detection engine that could allow an unauthenticated, remote attacker to bypass a configured File Policy for HTTP. The vulnerability is due to incorrect detection of modified HTTP packets used in chunked responses. An attacker could exploit this vulnerability by sending crafted HTTP packets through an affected device. A successful exploit could allow the attacker to bypass a configured File Policy for HTTP packets and deliver a malicious payload. (CVE-2020-3299)

Multiple Cisco products are affected by a vulnerability in the Snort detection engine that could allow an unauthenticated, remote attacker to bypass the configured file policies on an affected system. The vulnerability is due to errors in how the Snort detection engine handles specific HTTP responses. An attacker could exploit this vulnerability by sending crafted HTTP packets that would flow through an affected system. A successful exploit could allow the attacker to bypass the configured file policies and deliver a malicious payload to the protected network. (CVE-2020-3315)

Multiple Cisco products are affected by a vulnerability in the Snort detection engine that could allow an unauthenticated, remote attacker to bypass a configured file policy for HTTP. The vulnerability is due to incorrect handling of an HTTP range header. An attacker could exploit this vulnerability by sending crafted HTTP packets through an affected device. A successful exploit could allow the attacker to bypass configured file policy for HTTP packets and deliver a malicious payload. (CVE-2021-1223)

Multiple Cisco products are affected by a vulnerability with TCP Fast Open (TFO) when used in conjunction with the Snort detection engine that could allow an unauthenticated, remote attacker to bypass a configured file policy for HTTP. The vulnerability is due to incorrect detection of the HTTP payload if it is contained at least partially within the TFO connection handshake. An attacker could exploit this vulnerability by sending crafted TFO packets with an HTTP payload through an affected device. A successful exploit could allow the attacker to bypass configured file policy for HTTP packets and deliver a malicious payload. (CVE-2021-1224)

Multiple Cisco products are affected by a vulnerability in the Snort application detection engine that could allow an unauthenticated, remote attacker to bypass the configured policies on an affected system. The vulnerability is due to a flaw in the detection algorithm. An attacker could exploit this vulnerability by sending crafted packets that would flow through an affected system. A successful exploit could allow the attacker to bypass the configured policies and deliver a malicious payload to the protected network. (CVE-2021-1236)

Multiple Cisco products are affected by vulnerabilities in the Snort detection engine that could allow an unauthenticated, remote attacker to bypass a configured file policy for HTTP. These vulnerabilities are due to incorrect handling of specific HTTP header parameters. An attacker could exploit these vulnerabilities by sending crafted HTTP packets through an affected device. A successful exploit could allow the attacker to bypass a configured file policy for HTTP packets and deliver a malicious payload. (CVE-2021-1494)

Multiple Cisco products are affected by a vulnerability in the Snort detection engine that could allow an unauthenticated, remote attacker to bypass a configured file policy for HTTP. The vulnerability is due to incorrect handling of specific HTTP header parameters. An attacker could exploit this vulnerability by sending crafted HTTP packets through an affected device. A successful exploit could allow the attacker to bypass a configured file policy for HTTP packets and deliver a malicious payload. (CVE-2021-1495)

A vulnerability in Server Name Identification (SNI) request filtering of Cisco Web Security Appliance (WSA), Cisco Firepower Threat…

Record
MGASA-2023-0117
Updated
2026-11-02

Affected products

Affected packages

Affected packages
PackageAffectedFixed
snort
Debian:10
before 2.9.20-0+deb10u1, plus listed versions
2.9.15.1-12.9.15.1-22.9.15.1-32.9.15.1-42.9.15.1-52.9.15.1-62.9.7.0-5
2.9.20-0+deb10u1
snort
Debian:11
before 2.9.20-0+deb11u1, plus listed versions
2.9.15.1-52.9.15.1-6
2.9.20-0+deb11u1
snort
Mageia:8
before 2.9.20-1.mga8
2.9.20-1.mga8
snort
Ubuntu:14.04:LTS
All versions, plus listed versions
2.9.2.2-32.9.5.3-32.9.6.0-0ubuntu1
None known
snort
Ubuntu:16.04:LTS
All versions, plus listed versions
2.9.7.0-5
None known
snort
Ubuntu:18.04:LTS
All versions, plus listed versions
2.9.7.0-52.9.7.0-5build1
None known
snort
Ubuntu:20.04:LTS
All versions, plus listed versions
2.9.7.0-5build1
None known

History

History
WhenChangedSources
2026-11-03aliases, publishedEUVD
2026-11-02createdCVE List, GitHub Advisories, NVD, OSV

References

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