Elo: Remote Code Execution in Elo Ruby backend via unescaped `#{...}` interpolation in emitted string literals and subtype-constraint labels
Written by anthropic/claude-haiku-5.5 from the sources below. Verify against them.
- Exploited
- Proof of concept public, per CISA
- Fix
- Fixed in 1.0.1
- Who is exposed
- Not reported
Do first: Upgrade to a fixed version: 1.0.1.
- Exploitation15/40CISA rates a proof of concept as public
- Exposure20/25No login or user action needed, CISA rates it automatable · Data gap: Advisories don't say whether default setups are affected
- Reach10/20Affects npm packages
- Severity10/10CVSS 9.8, total technical impact per CISA
- No patch0/5No signal
What would change the score
- Would score about 85 if added to CISA KEV
- Would score about 80 if CISA's SSVC rates exploitation active
- Would score about 60 if advisories confirm default setups are exposed
CVE-2026-44266 is not in CISA's Known Exploited Vulnerabilities (KEV) catalog. No public exploit code is tracked. It is rated CVSS 9.8 (critical) and affects elo; fixed in 1.0.1.
- Last modified
- Where the record stands: published, rejected by its publisher, or superseded by another id.What do these mean? →
- Published
- Whether CISA lists it in its Known Exploited Vulnerabilities catalog: proof that attackers are using it.What do these mean? →
- Not listed in CISA KEV
- A 0-100 score for how much a CVE matters across the industry: exploitation, exposure, how widely the software is used, severity and whether a fix exists.What do these mean? →
- 55/100 · provisional
- How many real-world setups can hit the bug, from the vendor's advisory and CISA data. It does not know your setup.What do these mean? →
- Unclear
- Fix
- Fixed in 1.0.1
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
- Exploitation: poc
- Automatable: yes
- Technical impact: total
Summary
Elo, a purely functional expression language for no-code tools, is affected when its Ruby compilation backend processes attacker-controlled text, including through the /try playground, the eloc command-line tool with the Ruby target, and programmatic parse-then-emit use. Successful exploitation would let an attacker run arbitrary Ruby code and shell commands on the system executing the compiled Ruby output.
Read the original description
Elo is a purely functional expression language for no-code tools. Prior to 1.0.1, the Ruby backend in src/compilers/ruby.ts embeds attacker-controlled text in Ruby double-quoted strings without escaping #, so Ruby interpolation forms in the string-literal emitter or the labelled subtype-constraint branch become executable Ruby. The affected entry points include the /try playground with the Ruby target, bin/eloc -t ruby -x, and defaultFormats.elo.parse() followed by Ruby emission. A failing labelled subtype constraint evaluates its message, while an ordinary string literal is evaluated when the compiled Ruby runs, allowing Ruby code and shell command execution through backticks. JavaScript, Python, and SQL emission are not affected by this Ruby-specific path. This issue is fixed in version 1.0.1.
Impact
- Widely used
@enspirit/elo has 757 weekly downloads.Source: npmjs.com
What to do
Upgrade to a fixed version: 1.0.1.
Timeline
- CVE published
- First seen by cve.now
- Posted on X by cve.now
- CISA SSVC assessment
Exploitation: poc · Automatable: yes · Technical impact: total
- Record last updated
Affected versions
- enspirit elo
fixed in 1.0.1
- @enspirit/elonpm
fixed in 1.0.1
Evidence 3
- Advisory
- Repository
- Repository
Corrections
None so far.
Something wrong on this page? Report an error. Every fix is listed here.
Questions about CVE-2026-44266
Is CVE-2026-44266 being exploited?
It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. CISA's SSVC assessment notes a proof of concept exists. No public exploit code is tracked.Source: cve.now feed data
Which versions are affected by CVE-2026-44266?
elo: before 1.0.1. @enspirit/elo (npm): before 1.0.1.Source: cve.now feed data
How do I fix CVE-2026-44266?
Upgrade to a fixed version: 1.0.1.Source: cve.now feed data