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NVD / CVE Program· CNA cisco

CVE-2020-3315: Multiple Cisco Products Snort HTTP Detection Engine File Policy Bypass Vulnerability

Noroxi assessment

Priority: Monitor (action score 22/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 2.2% (FIRST EPSS); higher than 82.5% of all records.
  • Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
  • According to CISA the attack is automatable: targets can be found by mass scanning.
  • Fixed version: snort (Debian:10) 2.9.20-0+deb10u1; snort (Debian:11) 2.9.20-0+deb11u1.

Low priority for now. Upgrade to snort (Debian:10) 2.9.20-0+deb10u1; snort (Debian:11) 2.9.20-0+deb11u1 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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.

MediumCVSS 5.3 · v3.1—No exploit Fix available
Published
May 6, 2020
Updated
Aug 11, 2026
EPSS
2.2% · 82th percentile

Report tools

JSON

Action score

22

Monitor

Low priority for now.

CVSS
21 / 40 · 5.3 / 10
CISA KEV
0 / 30 · Not listed
EPSS
1 / 30 · 2.2%

CISA SSVC decision

Exploitation
none
Automatable
yes
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
5.3
CNA · cisco
5.8
0.5 point gap

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2020-3315

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
ciscosecure firewall management center
ciscosecure firewall threat defense
ciscoios
cisco1100-4g integrated services router
cisco1100-6g integrated services router
cisco1100-lte integrated services router
cisco1101 integrated services router
cisco1109 integrated services router
cisco1111x integrated services router
cisco111x integrated services router
cisco1120 integrated services router
cisco1160 integrated services router

and 7 more

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • cisco ios15.2(7)e
  • cisco ios16.11.2
  • cisco ios17.3.1
  • cisco secure firewall management center2.9.14.4
  • cisco secure firewall management center2.9.15
  • cisco secure firewall management center2.9.16
  • cisco secure firewall threat defensebefore 6.6.0

Versions reported by the vendor

Affected version ranges reported by the assigning authority (cisco). Independent of NVD's CPE analysis and usually ahead of it.

  • Cisco Cisco Firepower Threat Defense Software

    • n/aaffected

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:10snortbefore 2.9.20-0+deb10u12.9.20-0+deb10u1
Debian:11snortbefore 2.9.20-0+deb11u12.9.20-0+deb11u1

Same product

cisco: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-20079Cisco Secure Firewall Management Center Authentication Bypass Remote Code Execution VulnerabilityKEV
    97Now
  • CVE-2026-20131Cisco Secure Firewall Management Center Software Remote Code Execution VulnerabilityKEV
    83Now
  • CVE-2026-20316Cisco Secure Firewall Management Center Software Static Credential VulnerabilityKEV
    62This week

Published before and after this one in the same product

  • ← EarlierCVE-2020-3312May 6, 2020 · Cisco Firepower Threat Defense Software Information Disclosure Vulnerability
    30Monitor
  • ← EarlierCVE-2020-3313May 6, 2020 · Cisco Firepower Management Center Cross-Site Scripting Vulnerability
    24Monitor
  • Later →CVE-2020-3318May 6, 2020 · Cisco Firepower Management Center Static Credential Vulnerabilities
    39Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
debian:snort2.9.20-0+deb10u1 · Debian:10Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

No history yet (it accumulates with the daily EPSS job).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
none
Integrity
low · data or configuration can be modified
Availability
none
Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
None
Integrity impact
Low
Availability impact
None

Weakness class (CWE)

CWE-693 · Protection Mechanism Failure

CVSS vector

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

nvd-primary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (2 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records