Is CVE-2021-1495 actively exploited?

No active exploitation of CVE-2021-1495 has been confirmed so far. Continue monitoring, as exploit status can change.

Can CVE-2021-1495 be exploited remotely?

Yes. CVE-2021-1495 is exploitable remotely over the network (CVSS attack vector: Network).

What is the CVSS score of CVE-2021-1495?

CVE-2021-1495 has a CVSS score of 5.3 (MEDIUM).

HOME VULNERABILITIESCVE-2021-1495

MEDIUM

CVE-2021-1495

CWE-755Published: April 29, 2021· Updated: Jun 17, 2026

5.3

CVSS v3.1

Official Description

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.

NVD Source

Technical Analysis

CVE-2021-1495 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.

The vulnerability requires no privileges and no user interaction, making it a prime target for automated exploitation campaigns and worm-like propagation.

CVSS v3.1 Vector Breakdown

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges Req.None

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityNone

IntegrityLow

AvailabilityNone

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

Affected Vendors & Products

Cisco21 product(s)

firepower threat defenseios xe1100-4g\/6g integrated services router1101 integrated services router1109 integrated services router1111x integrated services router111x integrated services router1120 integrated services router1160 integrated services router3000 integrated services router4221 integrated services router4331 integrated services router+9

snort1 product(s)

snort

Source: NVD CPE · 22 total CPE entries