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CVE-2018-8879· NVD / CVE Program· CNA mitre

Stack-based buffer overflow in Asuswrt-Merlin firmware for ASUS devices older than 384.4 and ASUS firmware before 3.0.0.4.382.50470 for devi

Stack-based buffer overflow in Asuswrt-Merlin firmware for ASUS devices older than 384.4 and ASUS firmware before 3.0.0.4.382.50470 for devices allows remote attackers to execute arbitrary code by providing a long string to the blocking.asp page via a GET or POST request. Vulnerable parameters are flag, mac, and cat_id.

CriticalCVSS 9.8 · v3.1—No exploit No fix recorded
Published
Nov 21, 2019
Updated
Jun 16, 2026
EPSS
17.2% · 97th percentile
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Action score

44

Plan

Add it to your regular patch cycle.

CVSS
39 / 40 · 9.8 / 10
CISA KEV
0 / 30 · Not listed
EPSS
5 / 30 · 17.2%

Noroxi analysis

No Noroxi analysis for this record yet

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Affected systems

VendorProduct
asusrt-ac66u firmware
asusrt-ac66u

Affected versions

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

  • asus rt-ac66u firmwarebefore 3.0.0.4.382.50470

Same product

asus: all records

Other highest-scoring records for the same primary product.

  • CVE-2013-4659Buffer overflow in Broadcom ACSD allows remote attackers to execute arbitrary code via a long string to TCP port 5916.
    43Plan
  • CVE-2013-4937Multiple unspecified vulnerabilities in the AiCloud feature on the ASUS RT-AC66U, RT-N66U, RT-N65U, RT-N14U, RT-N16, RT-N56U, and DSL-N55U w
    41Plan
  • CVE-2013-4656Symlink Traversal vulnerability in ASUS RT-AC66U and RT-N56U due to misconfiguration in the SMB service.
    40Plan
  • CVE-2018-9285Main_Analysis_Content.asp in /apply.cgi on ASUS RT-AC66U, RT-AC68U, RT-AC86U, RT-AC88U, RT-AC1900, RT-AC2900, and RT-AC3100 devices before 3
    40Plan
  • CVE-2014-2719Advanced_System_Content.asp in the ASUS RT series routers with firmware before 3.0.0.4.374.5517, when an administrator session is active, al
    25Monitor
  • CVE-2020-7997ASUS WRT-AC66U 3 RT 3.0.0.4.372_67 devices allow XSS via the Client Name field to the Parental Control feature.
    24Monitor

Remediation

Which version to upgrade to

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

No fix version is recorded for this entry. Check the references for vendor advisories.

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.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

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
high · data can be read
Integrity
high · data or configuration can be modified
Availability
high · the service can be disrupted
Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
High
Integrity impact
High
Availability impact
High

Weakness class (CWE)

CWE-787 · Out-of-bounds Write

CVSS vector

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

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.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

No changes recorded on tracked fields yet. Score, KEV, exploit maturity and fix status changes appear here.

References

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

All records