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ScreenApplication · Gnu

CVE-2007-3048

HIGH · 7.2 CVSS v2.0 Published 2007-06-05
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
77/100
Remediation priority · High
No privileges Zero-click

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 · unedited
GNU screen 4.0.3 allows local users to unlock the screen via a CTRL-C sequence at the password prompt. NOTE: multiple third parties report inability to reproduce this issue

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 · low confidence

GNU screen 4.0.3 has a vulnerability where pressing CTRL-C at the password prompt during screen locking bypasses authentication, allowing unauthorized access to the unlocked screen session. The issue stems from improper signal handling that fails to ignore SIGINT at the password entry screen.

MitigationApply vendor patches or upgrade to a patched version of GNU screen; alternatively, avoid using screen's built-in lock feature in untrusted multi-user environments until the issue is resolved.

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
ScreenApplication
Affected:= 4.0.3

CVSS 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
Authentication
None
Confidentiality
Complete
Integrity
Complete
Availability
Complete

AV:L/AC:L/Au:N/C:C/I:C/A:C

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 checks

Work through these to decide whether this CVE applies to you.

  1. Check installed GNU screen version
    Run 'screen --version' or 'screen -v' to display the version number
    Affected if The version displayed is exactly 4.0.3
  2. Identify running screen sessions
    Run 'screen -ls' to list all active screen sessions on the system
    Affected if Any sessions exist and the screen binary version is 4.0.3
  3. Check if screen lock feature is configured
    Inspect the screen configuration files (~/.screenrc or /etc/screenrc) for 'password' or 'lock' directives, or check if users have set a lock password using the ':password' screen command
    Affected if A lock password is configured or the lock feature has been used in any session
  4. Verify signal handling at lock prompt
    Attempt to lock a session (Ctrl-a x) and press Ctrl-C at the password prompt; observe whether the session unlocks without requiring the password
    Affected if Pressing Ctrl-C at the password prompt grants access without authentication

You are affected if GNU screen version 4.0.3 is installed AND the built-in screen lock feature is in use, allowing Ctrl-C to bypass password authentication.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

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 data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Apply vendor patches or upgrade to a patched version of GNU screen; alternatively, avoid using screen's built-in lock feature in untrusted multi-user environments until the issue is resolved.

Fix this in Screen Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA4.0 h
22.0 hours of engineering $3,860
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2007-3048 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
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