CVE-2021-1495 json
Multiple Cisco Products Snort HTTP Detection Engine File Policy Bypass Vulnerability
published 2021-04-29 5 y ago modified 2026-08-11 2 mo ago also EUVD-2021-6962
- cvss
- 5.8
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 1.7%
- EPSS 1.7% chance of exploitation in 30 days, percentile 77%
- public exploits
- 0
- none known
Summary
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.
Patch / fix
- cisco secure_firewall_threat_defense 6.4.0.12, 6.6.4, 6.7.0.2
- cisco ios_xe 16.12.5, 17.3.3, 17.4.1
- snort snort 2.9.17.1
CISA SSVC
- Exploitation
- none
- Automatable
- yes
- Technical impact
- partial
- Assessed
- 2 y ago
Exploit prediction
1.73% chance of exploitation in the next 30 days, higher than 77% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 5.8 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N |
| NVD | 3.1 | 5.3 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N |
| NVD | 2.0 | 5.0 | AV:N/AC:L/Au:N/C:N/I:P/A:N |
Affected products
- Cisco Cisco Firepower Threat Defense Software
Classification
- Weakness
-
- CWE-755 Improper Handling of Exceptional Conditions
- Technology feeds
References
-
tools.cisco.com
/security/center/content/CiscoSecurityAdvisory/cisco-sa-http-fp-bp-KfDdcQhc
vendor-advisory
-
debian.org
/security/2023/dsa-5354
vendor-advisory
-
lists.debian.org
/debian-lts-announce/2023/02/msg00011.html
mailing-list
Sources
- CVE List CVE-2021-1495
- NVD CVE-2021-1495
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