Debian LinuxOperating system · Debian
CVE-2019-9924
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedrbash in Bash before 4.4-beta2 did not prevent the shell user from modifying BASH_CMDS, thus allowing the user to execute any command with the permissions of the shell.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · high confidencerbash (restricted Bash) in versions before 4.4-beta2 did not prevent shell users from modifying the BASH_CMDS internal array, allowing a restricted user to bypass rbash constraints and execute arbitrary commands with the shell's full permissions. This enables privilege escalation within restricted shell environments.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data
Debian LinuxOperating system
= 8.0
Ubuntu LinuxOperating system
= 12.04= 14.04= 16.04< 4.4= 4.4= 42.3all versionsall versionsCVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Local
- Complexity
- Low
- Privileges
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Identify installed Bash versionRun 'bash --version' or check package manager (dpkg -l | grep bash for Debian/Ubuntu, rpm -qa | grep bash for RHEL/SUSE)Affected if Version is 4.4 or any version earlier than 4.4 (versions before 4.4-beta2 are vulnerable)
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Confirm rbash is present on the systemVerify /bin/rbash or /usr/bin/rbash exists, or check if rbash is listed in /etc/shellsAffected if rbash binary exists and is listed as an available shell
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Check for user accounts configured to use rbashInspect /etc/passwd for any users with rbash as their login shell (look for '/bin/rbash' or '/usr/bin/rbash' in the last field)Affected if Any user account has rbash assigned as its login shell
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Verify the specific vulnerability in Bash 4.4Check if the Bash patch for BASH_CMDS protection is applied - compare your bash version string against 4.4-beta2 release notes or check patch status via vendor security advisoriesAffected if Running Bash 4.4 without the beta2 patch applied
You are affected if any system runs Bash version 4.4 or earlier AND has user accounts configured to use rbash as their login shell.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
From vendor data4.4
Upgrade to Bash 4.4-beta2 or later to obtain the patched rbash version. Additionally, review all rbash deployments and ensure proper configuration with complementary security controls.
Fix this in Debian Linux
Scoped from the published advisory
- Consultation2.0 h
- Implementation2.0 h
- Testing3.0 h
- Review / QA1.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,224.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2019-9924 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2019-9924 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
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