CVE-2020-3299
Multiple Cisco Products SNORT HTTP Detection Engine File Policy Bypass Vulnerability
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
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 Medium
CVSS: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 Medium
CVSS: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 Medium
CVSS: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 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N - CVSS 3.0
- 5.8 Medium
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N - CVSS 2.0
- 5.0 Medium
AV: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 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N - CVSS 3.0
- 5.8 Medium
CVSS: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
| Package | Affected | Fixed |
|---|---|---|
snortDebian: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 |
snortDebian:11 |
before 2.9.20-0+deb11u1, plus listed versions 2.9.15.1-52.9.15.1-6 |
2.9.20-0+deb11u1 |
snortMageia:8 |
before 2.9.20-1.mga8 | 2.9.20-1.mga8 |
snortUbuntu:14.04:LTS |
All versions, plus listed versions 2.9.2.2-32.9.5.3-32.9.6.0-0ubuntu1 |
None known |
snortUbuntu:16.04:LTS |
All versions, plus listed versions 2.9.7.0-5 |
None known |
snortUbuntu:18.04:LTS |
All versions, plus listed versions 2.9.7.0-52.9.7.0-5build1 |
None known |
snortUbuntu:20.04:LTS |
All versions, plus listed versions 2.9.7.0-5build1 |
None known |
History
| When | Changed | Sources |
|---|---|---|
| 2026-11-03 | aliases, published | EUVD |
| 2026-11-02 | created | CVE List, GitHub Advisories, NVD, OSV |
References
tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-ftd-bypass-3eCfd24j
lists.debian.org/debian-lts-announce/2023/02/msg00011.html
debian.org/security/2023/dsa-5354
nvd.nist.gov/vuln/detail/CVE-2020-3299
github.com/advisories/GHSA-j2v5-cw33-rvx6
advisories.mageia.org/MGASA-2023-0117.html
Left out here: the rest of 1 source description. The JSON record has them.