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CVE-2026-121931

Linksys WRT54GL Traceroute Diagnostic Function apply.cgi system os command injection

CVSS score

9.4

EPSS probability

—

Risk score

0.9

Published

2 h ago

Patch status has not yet been verified

Resmî kaynaklarda yeterli kanıt bulunamadı. Bu sonuç “yama yok” anlamına gelmez.

Impact on My Inventory

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Vulnerability description

DayBreach AI Explanation

Verified against sources

Linksys WRT54GL apply.cgi OS Command Injection Vulnerability

Sources read

1

Source agreement

Tam uyum

Evidence confidence

%55

Short explanation

A security vulnerability has been detected in Linksys WRT54GL 4.30.18 affecting the system function of the apply.cgi file within the Traceroute Diagnostic Function component. This flaw leads to OS command injection and can be launched remotely.

Why does it matter?

This critical vulnerability allows remote attacks and poses additional risks because the affected product is no longer supported by the maintainer.

What should be done?

  • Follow vendor advisories
  • Evaluate alternative mitigations given the product is unsupported
Chain of evidence and sources3 verified claims

Linksys WRT54GL 4.30.18 sürümünde Traceroute Diagnostic Function içerisindeki apply.cgi dosyasında işletim sistemi komut enjeksiyonu zafiyeti bulunmaktadır.

Zafiyet uzaktan tetiklenebilmekte olup istismarı halka açık şekilde paylaşılmıştır.

Etkilenen ürün artık üretici veya bakım sağlayıcı tarafından desteklenmemektedir.

Show the technical text from the sources

A security vulnerability has been detected in Linksys WRT54GL 4.30.18. The impacted element is the function system of the file apply.cgi of the component Traceroute Diagnostic Function. Such manipulation of the argument traceroute_ip leads to os command injection. The attack can be launched remotely. The exploit has been disclosed publicly and may be used. The vendor was contacted early about this disclosure but did not respond in any way. This vulnerability only affects products that are no longer supported by the maintainer.

CVSS vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:P

CWE: CWE-78, CWE-77

This explanation was compiled automatically from the source records. Scores, active exploitation, patch and exploit status come straight from the sources.

IMPACT: Affected Products and Software

Affected Products

The following products are affected by CVE-2026-121931 vulnerability. Where our threat engine knows the exact affected versions, they are listed below.

IDVENDORPRODUCTACTION
1linksyswrt54gl View
Total affected vendors: 1|Products: 1

RED HAT CSAF/VEX: Product Impact Check

Red Hat has not yet published a CSAF/VEX impact record for this CVE. This does not mean “not affected”.

SCORING: CVSS from Multiple Sources

CVSS Scores

The Common Vulnerability Scoring System is a standardised framework for assessing the severity of vulnerabilities in software and systems. We collect and display CVSS scores from several sources for each CVE.

SCOREVERSIONSEVERITYVECTORSOURCE
9.4CVSS V4_0CRITICALCVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:PCVE CNA
9.1CVSS V3_1CRITICALCVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H/E:P/RL:X/RC:CCVE CNA
9.1CVSS V3_0CRITICALCVSS:3.0/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H/E:P/RL:X/RC:CCVE CNA
9.1CVSS V31CRITICALCVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:HNVD
8.5CVSS V40HIGHCVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:P/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:XNVD
8.3CVSS V2_0—AV:N/AC:L/Au:M/C:C/I:C/A:C/E:POC/RL:ND/RC:CCVE CNA
8.3CVSS V2—AV:N/AC:L/Au:M/C:C/I:C/A:CNVD

Patch and Remediation Guide

Solution & Remediation Advisory

Patch status unknown

İncelenen resmî kaynaklarda yama durumu doğrulanamadı. Bu sonuç “yama yok” anlamına gelmez.

Confirm the affected product and version against the source evidence above.
Restrict access to internet-facing services and apply network segmentation.
Until a patch is confirmed, follow the vendor advisory; do not read an unknown status as “no patch”.
Monitor server logs and network endpoints for signs of anomalous execution.

Public exploit and active exploitation status

Verified exploit intelligence

No verified public PoC, exploit repository or Metasploit module has been found for this CVE yet.

Weakness Classification and Attack Patterns (CWE & CAPEC)

CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorises the common flaws or weaknesses that can lead to vulnerabilities. CVE-2026-121931 is associated with the following CWEs:

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2026-121931 weaknesses.

Attack Vector and Accessibility

ExposureAğ üzerinden
PermissionsHigh
UserGerekmiyor

Official Sources and Advisories

CVSS Vector Radar Chart

9.4 / 10
Attack VectorNetworkComplexityLowPrivilegesHighUser Interact.NoneConfidentialityLowIntegrityNoneAvailabilityHigh

Vulnerability Scoring Details

CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:P
Attack VectorNetwork
Attack ComplexityLow
Privileges RequiredHigh privileges
User InteractionNone required
Confidentiality (Gizlilik)Low
Integrity (Bütünlük)None
Availability (Erişilebilirlik)High

Yama durumu bilinmiyor

İncelenen resmî kaynaklarda yama durumu doğrulanamadı. Bu sonuç “yama yok” anlamına gelmez.

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Weakness Type (CWE & CAPEC)

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CVE-2026-121931 · Linksys WRT54GL Traceroute Diagnostic…