CVSS 3.1
5.3 mediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:NCVE-2026-124738 Busybox: httpd password rule bypass for pre-compressed .gz files via accept-encoding: gzip
Medium (5.3) in red hat. EPSS 0.5% estimated probability of exploitation activity in the next 30 days.
On this page
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.
Severity
- EPSS
- 0.5% estimated probability of exploitation activity in the next 30 days; 43rd percentile. Scored 2026-11-13. A forecast for this CVE across the internet, not for your own systems.
- CISA's assessment (SSVC)
- Exploitation: none · Automatable: yes · Technical impact: partial, assessed 2026-11-12. From CISA's Vulnrichment in the CVE List: whether it is exploited, whether exploiting it can be automated, and how much control it gives.
- CWE
- CWE-288 Authentication Bypass Using an Alternate Path or Channel
- OWASP Top 10
- A07:2025 Authentication Failures
- Published
- Modified
- Assigned by
- redhat (CNA)
- NVD analysis
- Awaiting analysis
- Record from
- the NVD, synced
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Affected
- red hat:red hat enterprise linux 6
- red hat:red hat hardened images
Linux distributions
| Distribution | Release | Package | Fixed in | Advisory |
|---|---|---|---|---|
| Ubuntu | 20.04:LTS, 22.04:LTS, 24.04:LTS and 5 more | busybox | no fix listed | UBUNTU-CVE-2026-124738 |
From the distributions' data via OSV.dev: Ubuntu Security Notices © Canonical Ltd., CC BY-SA 4.0. Modified: reformatted and linked to CVE records. Credits. On the distributions' own pages: Ubuntu.
Red Hat
Red Hat rates this Moderate.
This vulnerability is assessed as Moderate rather than Important because exploitation is constrained to niche configurations where authentication directives explicitly target individual compressed archive filenames instead of directory paths. In Red Hat enterprise distributions, BusyBox is generally restricted to lightweight recovery shells and initramfs environments rather than standalone production web services. Consequently, exposure of the embedded httpd service with pre-compressed file serving is uncommon under default installations.
To mitigate this vulnerability without modifying binary features, apply one of the following configuration measures:
1. Configure directory-level authentication:
In the BusyBox `httpd.conf` configuration file, define authentication rules covering the containing directory rather than individual file paths. Directory rules are evaluated against both the base request and served compressed variants.
2. Protect base filenames:
When individual file protection is necessary, configure password rules for both the uncompressed filename and the `.gz` filename (for example, applying the directive to both `/secret.txt` and `/secret.txt.gz`).
3. Restrict service access:
Restrict network reachability to the BusyBox httpd daemon using local firewall rules if remote access is not required.
Warning: Applying changes to httpd.conf requires restarting or reloading the BusyBox httpd process, which will temporarily terminate active network sessions.
| Product | Package | State | Advisory |
|---|---|---|---|
| Red Hat Enterprise Linux 6 | busybox | Not affected | |
| Red Hat Hardened Images | busybox | Affected |
Contains Red Hat Security Data © Red Hat, Inc., licensed under CC BY 4.0. Source: https://access.redhat.com/security/data. Modified: reformatted. Red Hat's page for CVE-2026-124738.
Attack patterns (CAPEC)
- CAPEC-127 Directory Indexing Likelihood: High · Severity: Medium
- CAPEC-665 Exploitation of Thunderbolt Protection Flaws Likelihood: Low · Severity: Very High
The attack patterns MITRE's CAPEC relates to this record's weaknesses, as MITRE names them. Credits.