CVE-2026-121931

Read full description

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 9.1 (CRITICAL)

Attention and evidence

HYPE SCORE

0.0/10

REALITY · THREAT PRIORITY

3.3/10

General review priority; not probability

Evidence confidence: Insufficient evidence

Why this priority?

Technical severity: CVSS 9.1: +3.18
Fresh EPSS: 2.72%: +0.07

General review priority, not probability, victim count or asset-specific risk. A range covers missing CVSS/EPSS inputs within the current evidence state.

Sources: 1 documents and public datasets.

Hype components

Headline sample (25%)

0/100

Press, 30 days (60%)

0/100

Grounded branding (15%)

0/100

HYPE TOTAL0/100

Sources and documents

Latest Vulnerabilities

Technical advisory · 04 Nov 2026, 18:45 · CVE-2026-121931 - Linksys WRT54GL Traceroute Diagnostic Function apply.cgi system os command injection

Score evolution

● Hype ● Reality

━ Hype Score (Perceived) ━ Reality threat priority. Definition changes are not new attacks.

Public exploit evidence

Public exploit entries / repo candidates

Evidence context and dated references

Reality is general threat/review priority, combining observed exploitation, CVSS severity and fresh EPSS. Evidence confidence is separate. This is not calibrated risk, a victim count or an asset-specific assessment. A range reflects missing numeric inputs. Published 2 days ago. Exploitation evidence usually takes weeks to show up: a low reality score can mean there is no data yet, not that the flaw is mild.

Evidence in context

Confidence in exploitation evidence: Insufficient evidence
Priority basis: Exploitation in attacks unconfirmed; CVSS 9.1; EPSS 2.7%
Attention, last 30 days: 0 distinct story titles; 0 press documents; 0 publisher domains.
Technical potential: network access, high privileges, no user interaction.
Observed activity: No exploitation observation is recorded.
Known scale: Not quantified.
Evidence confidence basis: Insufficient evidence

Score evaluated: 2026-11-05 13:59:56.876805+00:00 · EPSS snapshot: 2026-11-05T12:03:04Z

Source event timeline

Published

04 Nov 2026, 18:45

Score calculated

05 Nov 2026, 13:59