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XtermApplication · Invisible Island

CVE-2023-40359

CRITICAL · 9.8 CVSS v3.1 Published 2023-08-14
Fix available
A fix is available. Upgrade to 380 or later.
See remediation →
100/100
Remediation priority · Urgent
Remotely reachable 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
xterm before 380 supports ReGIS reporting for character-set names even if they have unexpected characters (i.e., neither alphanumeric nor underscore), aka a pointer/overflow issue. This can only occur for xterm installations that are configured at compile time to use a certain experimental feature.

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 · moderate confidence

xterm before version 380 contains a pointer overflow vulnerability in its ReGIS character-set reporting functionality. When processing character-set names containing unexpected characters (neither alphanumeric nor underscore), improper bounds checking allows memory corruption. This issue only affects xterm installations compiled with a specific experimental feature enabled, significantly limiting the attack surface.

MitigationUpgrade xterm to version 380 or later. If upgrading is not immediately feasible, recompile xterm without the experimental ReGIS feature to eliminate the attack vector.

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
XtermApplication
Affected:< 380

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
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/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 checks

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

  1. Check installed xterm version
    Run 'xterm -version' or 'xterm -v' to determine the version number
    Affected if Version is less than 380 (e.g., 379, 378, etc.)
  2. Determine if ReGIS support was compiled in
    Check xterm's compile-time configuration: look for '--enable-regis' in 'xterm -help' output, or inspect the binary for ReGIS-related strings with 'strings xterm | grep -i regis', or review the build configuration used when xterm was compiled
    Affected if ReGIS experimental feature was enabled at compile time (this feature is not enabled by default in most distributions)
  3. Verify character-set input method is accessible
    Determine if the ReGIS graphics mode can be invoked - this typically requires applications that use ReGIS terminal sequences, or manual testing with '\x1b[2g' escape sequences that trigger character-set reporting
    Affected if ReGIS functionality is accessible and xterm responds to ReGIS control sequences in the terminal

User is affected only if running xterm version < 380 AND the xterm binary was compiled with the experimental ReGIS feature enabled; simply having an old version without ReGIS support does not expose this vulnerability.

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.

dbcve · scoped
Upgrade available Upgrade to 380 or later
Fixed in 380
Interim mitigation

Upgrade xterm to version 380 or later. If upgrading is not immediately feasible, recompile xterm without the experimental ReGIS feature to eliminate the attack vector.

Recommended fix Moderate confidence

xterm 380

  1. Check current xterm version by running: xterm -version
  2. Identify if your xterm was compiled with ReGIS support (experimental feature) - this is typically not enabled by default in most distributions
  3. For systems with package managers: update to the latest package version which should include xterm 380 or later
  4. If building from source: download xterm version 380 or later from invisible-island.net and rebuild with your preferred configuration
  5. Verify the fix by running: xterm -version (should show 380 or higher)
  6. If using ReGIS experimental feature, test that character-set name reporting works correctly with alphanumeric and underscore characters only
Caveat Minimal - the fix addresses an edge case in an experimental compile-time feature; normal xterm usage unaffected

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Xterm Scoped from the published advisory
  • Consultation4.0 h
  • Implementation6.0 h
  • Testing6.0 h
  • Review / QA3.0 h
19.0 hours of engineering $3,320
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $5,312.

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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-2023-40359 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
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data