CVE-2023-41037 is a medium-severity (CVSS 4.3) CWE-347 vulnerability in openpgp. 1 public exploit reference exists, so weaponization risk is real. O3 Security confirms whether CVE-2023-41037 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Cleartext Signed Message Signature Spoofing in openpgpjs
Exploitation Status
No confirmed exploitation observed yet
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2023-41037.
Real-World Exposure
How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.
openpgpnpmDescription
OpenPGP.js is a JavaScript implementation of the OpenPGP protocol. In affected versions OpenPGP Cleartext Signed Messages are cryptographically signed messages where the signed text is readable without special tools. These messages typically contain a "Hash: ..." header declaring the hash algorithm used to compute the signature digest. OpenPGP.js up to v5.9.0 ignored any data preceding the "Hash: ..." texts when verifying the signature. As a result, malicious parties could add arbitrary text to a third-party Cleartext Signed Message, to lead the victim to believe that the arbitrary text was signed. A user or application is vulnerable to said attack vector if it verifies the CleartextMessage by only checking the returned verified property, discarding the associated data information, and instead visually trusting the contents of the original message. Since verificationResult.data would always contain the actual signed data, users and apps that check this information are not vulnerable. Similarly, given a CleartextMessage object, retrieving the data using getText() or the text field returns only the contents that are considered when verifying the signature. Finally, re-armoring a CleartextMessage object (using armor() will also result in a "sanitised" version, with the extraneous text being removed. This issue has been addressed in version 5.10.1 (current stable version) which will reject messages when calling openpgp.readCleartextMessage() and in version 4.10.11 (legacy version) which will will reject messages when calling openpgp.cleartext.readArmored(). Users are advised to upgrade. Users unable to upgrade should check the contents of verificationResult.data to see what data was actually signed, rather than visually trusting the contents of the armored message.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | openpgp | all versions | 4.10.11 |
| 📦npm | openpgp | ≥ 5.0.0&&< 5.10.1 | 5.10.1 |
Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for openpgp. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update openpgp to 4.10.11 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2023-41037 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether CVE-2023-41037 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to CVE-2023-41037. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2023-41037 in your dependencies?
O3 detects CVE-2023-41037 across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.