High · CVSS 7.5CVE-2026-124737

Busybox: heap buffer overflow in the tftp client on fallback to the default block sizeCVE-2026-124737

Answer in brief

CVE-2026-124737 records a High severity (CVSS 7.5) vulnerability in Busybox: heap buffer overflow in the tftp client on fallback to the default block size. The current sources do not mark it as known exploited. The current feed maps Red Hat/busybox (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Nov 11, 2026Updated Nov 11, 2026Source checked Nov 11, 2026First seen by HOL Nov 11, 2026Material review Nov 11, 2026

Upstream Advisory

Key facts

Risk: High · CVSS 7.5
Exploitation: Not marked as known exploited
Affected software: 1 mapped package or product
Fix availability: Not reported

Why this deserves its current priority

CVSS is 7.5. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps Red Hat/busybox (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
Red Hat/busyboxgeneric	*	Not reported

Recommended response

Check inventory. Check lockfiles and deployed manifests for Red Hat/busybox.
Review the reported fix. Source-reported workaround: Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.

Evidence timeline and material changes

Published upstream
Nov 11, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Nov 11, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Nov 11, 2026

Sources and claim methodology

Upstream source description

A flaw was found in BusyBox. When the TFTP (Trivial File Transfer Protocol) client requests a custom small block size and receives a standard response, it falls back to the default block size without resizing the allocated memory buffer. A malicious TFTP server can exploit this issue by sending standard-sized network packets during a transfer, causing a heap buffer overflow. This flaw allows an attacker to achieve arbitrary code execution or cause a Denial of Service (DoS) by crashing the application.

Quoted source text, attributed separately from HOL analysis.

Package

Affected range

Fixed version

Red Hat/busyboxgeneric

Not reported

Recommended response

Check inventory. Check lockfiles and deployed manifests for Red Hat/busybox.

Review the reported fix. Source-reported workaround: Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.

Sources and claim methodology

Upstream source description

Quoted source text, attributed separately from HOL analysis.