The expansion of '\h' in the prompt string in bash 4.3 allows remote authenticated users…
Priority MEDIUM 44CWE-78Published · Updated
Key facts
- Attack vector
- Network
- Privileges required
- Low
- User interaction
- None
- Attack complexity
- High
- Impact type
- Code execution
- Confidentiality · integrity · availability
- High · High · High
- Fix status
- Partial Red Hat: 16 fixed, 1 without a fix
Attack profile from CVSS 3.0 · NVD. Fix status from CNA and Red Hat. Impact type from CWE-78.
Summary
The expansion of '\h' in the prompt string in bash 4.3 allows remote authenticated users to execute arbitrary code via shell metacharacters placed in 'hostname' of a machine.
Why it matters now
Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.06019 93rd percentileScored 2026-11-07
Fix Partial Red Hat: 2 advisoriesRed Hat: 16 fixed, 1 without a fix
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Total
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| — | — | all versions | — | No fix listed | CNA |
- — Vendor— Affected all versions Fixed in — No fix listed CNA
Remediation
Red Hat 2 advisories
- RHSA-2017:1931 Released 2017-08-01 · Red Hat rating Moderatebash security and bug fix update
- Red Hat Enterprise Linux Client (v. 7) bash-4.2.46-28.el7
- Red Hat Enterprise Linux Client Optional (v. 7) bash-doc-4.2.46-28.el7
- Red Hat Enterprise Linux ComputeNode (v. 7) bash-4.2.46-28.el7
- Red Hat Enterprise Linux ComputeNode Optional (v. 7) bash-doc-4.2.46-28.el7
- Red Hat Enterprise Linux Server (v. 7) bash-4.2.46-28.el7
- Red Hat Enterprise Linux Server Optional (v. 7) bash-doc-4.2.46-28.el7
- Red Hat Enterprise Linux Workstation (v. 7) bash-4.2.46-28.el7
- Red Hat Enterprise Linux Workstation Optional (v. 7) bash-doc-4.2.46-28.el7
- RHSA-2017:0725 Released 2017-03-21 · Red Hat rating Moderatebash security and bug fix update
- Red Hat Enterprise Linux Desktop (v. 6) bash-4.1.2-48.el6
- Red Hat Enterprise Linux Desktop Optional (v. 6) bash-doc-4.1.2-48.el6
- Red Hat Enterprise Linux HPC Node (v. 6) bash-4.1.2-48.el6
- Red Hat Enterprise Linux HPC Node Optional (v. 6) bash-doc-4.1.2-48.el6
- Red Hat Enterprise Linux Server (v. 6) bash-4.1.2-48.el6
- Red Hat Enterprise Linux Server Optional (v. 6) bash-doc-4.1.2-48.el6
- Red Hat Enterprise Linux Workstation (v. 6) bash-4.1.2-48.el6
- Red Hat Enterprise Linux Workstation Optional (v. 6) bash-doc-4.1.2-48.el6
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 5 | Affected | No fix planned: Will not fix |
| Red Hat Enterprise Linux Client (v. 7) | Fixed | RHSA-2017:1931 |
| Red Hat Enterprise Linux Client Optional (v. 7) | Fixed | RHSA-2017:1931 |
| Red Hat Enterprise Linux ComputeNode (v. 7) | Fixed | RHSA-2017:1931 |
| Red Hat Enterprise Linux ComputeNode Optional (v. 7) | Fixed | RHSA-2017:1931 |
| Red Hat Enterprise Linux Desktop (v. 6) | Fixed | RHSA-2017:0725 |
| Red Hat Enterprise Linux Desktop Optional (v. 6) | Fixed | RHSA-2017:0725 |
| Red Hat Enterprise Linux HPC Node (v. 6) | Fixed | RHSA-2017:0725 |
| Red Hat Enterprise Linux HPC Node Optional (v. 6) | Fixed | RHSA-2017:0725 |
| Red Hat Enterprise Linux Server (v. 6) | Fixed | RHSA-2017:0725 |
| Red Hat Enterprise Linux Server (v. 7) | Fixed | RHSA-2017:1931 |
| Red Hat Enterprise Linux Server Optional (v. 6) | Fixed | RHSA-2017:0725 |
| Red Hat Enterprise Linux Server Optional (v. 7) | Fixed | RHSA-2017:1931 |
| Red Hat Enterprise Linux Workstation (v. 6) | Fixed | RHSA-2017:0725 |
| Red Hat Enterprise Linux Workstation (v. 7) | Fixed | RHSA-2017:1931 |
| Red Hat Enterprise Linux Workstation Optional (v. 6) | Fixed | RHSA-2017:0725 |
| Red Hat Enterprise Linux Workstation Optional (v. 7) | Fixed | RHSA-2017:1931 |
Timeline
- 2026-10-02 Threatist record created from CVE-2016-0634
- 2026-10-03 Alias added: GHSA-h2ww-3j54-pccx
References
Patch 2
Advisory 12
- [oss-security] 20160927 Re: Re: CVE-2016-0634 -- bash prompt expanding $HOSTNAME
- RHSA-2017:0725
- [oss-security] 20160929 Re: Re: CVE-2016-0634 -- bash prompt expanding $HOSTNAME
- [oss-security] 20160920 Re: CVE-2016-0634 -- bash prompt expanding $HOSTNAME
- RHSA-2017:1931
- [oss-security] 20161007 Re: Re: CVE-2016-0634 -- bash prompt expanding $HOSTNAME
- [oss-security] 20160918 Re: CVE-2016-0634 -- bash prompt expanding $HOSTNAME
- [oss-security] 20160919 Re: CVE-2016-0634 -- bash prompt expanding $HOSTNAME
- [oss-security] 20161010 Re: Re: CVE-2016-0634 -- bash prompt expanding $HOSTNAME
- [oss-security] 20160916 Re: CVE-2016-0634 -- bash prompt expanding $HOSTNAME
- GLSA-201612-39
- [oss-security] 20161010 RE: Re: CVE-2016-0634 -- bash prompt expanding $HOSTNAME
More GNU Bash vulnerabilities
- TI-2014-05975 GNU Bash through 4.3 bash43-025 processes trailing strings after certain malformed… KEVCVSS 3.1CRITICAL 9.8
- TI-2014-05157 GNU Bash through 4.3 processes trailing strings after function definitions in the values… KEVCVSS 3.1CRITICAL 9.8
- TI-2014-05164 GNU Bash through 4.3 bash43-026 does not properly parse function definitions in the… KEVCVSS 3.1HIGH 8.8
- TI-2014-05988 The redirection implementation in parse.y in GNU Bash through 4.3 bash43-026 allows… CVSS 2.0HIGH 10.0
- TI-2014-05163 GNU Bash through 4.3 bash43-026 does not properly parse function definitions in the… CVSS 2.0HIGH 10.0
- TI-2014-05989 Off-by-one error in the read_token_word function in parse.y in GNU Bash through 4.3… CVSS 2.0HIGH 10.0
Sources
- CVE-2016-0634 · CVE Program
- CVE-2016-0634 · NVD
- FIRST EPSS
- GHSA-h2ww-3j54-pccx · GitHub Advisory Database · CC BY 4.0
- CVE-2016-0634 · Red Hat security data · CC BY 4.0
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