Summary
OpenPGP.js's message signature verification can be spoofed
Workarounds
- When verifying inline-signed messages, extract the message and signature(s) from the message returned by
openpgp.readMessage, and verify the(/each) signature as a detached signature by passing the signature and a new message containing only the data (created usingopenpgp.createMessage) toopenpgp.verify. - When decrypting and verifying signed+encrypted messages, decrypt and verify the message in two steps, by first calling
openpgp.decryptwithoutverificationKeys, and then passing the returned signature(s) and a new message containing the decrypted data (created usingopenpgp.createMessage) toopenpgp.verify.
Acknowledgements
We would like to thank:
- Edoardo Geraci and Thomas Rinsma of Codean Labs for finding and reporting this vulnerability
- The Sovereign Tech Agency for sponsoring the OpenPGP.js bug bounty program
- YesWeHack for hosting the OpenPGP.js bug bounty program
Impact
A maliciously modified message can be passed to either openpgp.verify or openpgp.decrypt, causing these functions to return a valid signature verification result while returning data that was not actually signed.
This flaw allows signature verifications of inline (non-detached) signed messages (using openpgp.verify) and signed-and-encrypted messages (using openpgp.decrypt with verificationKeys) to be spoofed, since both functions return extracted data that may not match the data that was originally signed. Detached signature verifications are not affected, as no signed data is returned in that case.
In order to spoof a message, the attacker needs a single valid message signature (inline or detached) as well as the plaintext data that was legitimately signed, and can then construct an inline-signed message or signed-and-encrypted message with any data of the attacker's choice, which will appear as legitimately signed by affected versions of OpenPGP.js.
In other words. any inline-signed message can be modified to return any other data (while still indicating that the signature was valid), and the same is true for signed+encrypted messages if the attacker can obtain a valid signature and encrypt a new message (of the attacker's choice) together with that signature.
Both OpenPGP.js v6 and v5 are affected. OpenPGP.js v4 is not affected.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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The issue has been patched in versions 5.11.3 and 6.1.1.
Frequently Asked Questions
- What is CVE-2025-47934? CVE-2025-47934 is a high-severity security vulnerability in openpgp (npm), affecting versions >= 5.0.1, <= 5.11.2. It is fixed in 5.11.3, 6.1.1.
- Which versions of openpgp are affected by CVE-2025-47934? openpgp (npm) versions >= 5.0.1, <= 5.11.2 is affected.
- Is there a fix for CVE-2025-47934? Yes. CVE-2025-47934 is fixed in 5.11.3, 6.1.1. Upgrade to this version or later.
- Is CVE-2025-47934 exploitable, and should I be worried? Whether CVE-2025-47934 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2025-47934 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2025-47934?
- Upgrade
openpgpto 5.11.3 or later - Upgrade
openpgpto 6.1.1 or later
- Upgrade