OpenPGP.js's message signature verification can be spoofed

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OpenPGP.js is a JavaScript implementation of the OpenPGP protocol. Startinf in version 5.0.1 and prior to versions 5.11.3 and 6.1.1, 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. The issue has been patched in versions 5.11.3 and 6.1.1. Some workarounds are available. 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 using `openpgp.createMessage`) to `openpgp.verify`. When decrypting and verifying signed+encrypted messages, decrypt and verify the message in two steps, by first calling `openpgp.decrypt` without `verificationKeys`, and then passing the returned signature(s) and a new message containing the decrypted data (created using `openpgp.createMessage`) to `openpgp.verify`.

Source published

19 May 2025 18:57:05 UTC

Source modified

20 May 2025 13:02:58 UTC

Saved here

23 Oct 2026 15:48:27 UTC

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CVE Program Terms of Use

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CVSS 4.0 · 8.7 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N

OpenPGP.js is a JavaScript implementation of the OpenPGP protocol. Startinf in version 5.0.1 and prior to versions 5.11.3 and 6.1.1, 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. The issue has been patched in versions 5.11.3 and 6.1.1. Some workarounds are available. 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 using `openpgp.createMessage`) to `openpgp.verify`. When decrypting and verifying signed+encrypted messages, decrypt and verify the message in two steps, by first calling `openpgp.decrypt` without `verificationKeys`, and then passing the returned signature(s) and a new message containing the decrypted data (created using `openpgp.createMessage`) to `openpgp.verify`.

Source published

May 19, 2025, 6:57:05 PM (timezone not stated)

Source modified

May 20, 2025, 1:02:58 PM (timezone not stated)

Saved here

15 Nov 2026 04:33:09 UTC

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EUVD CVSS 4.0 · 8.7 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N

OpenPGP.js is a JavaScript implementation of the OpenPGP protocol. Startinf in version 5.0.1 and prior to versions 5.11.3 and 6.1.1, 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. The issue has been patched in versions 5.11.3 and 6.1.1. Some workarounds are available. 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 using `openpgp.createMessage`) to `openpgp.verify`. When decrypting and verifying signed+encrypted messages, decrypt and verify the message in two steps, by first calling `openpgp.decrypt` without `verificationKeys`, and then passing the returned signature(s) and a new message containing the decrypted data (created using `openpgp.createMessage`) to `openpgp.verify`.

Source published

19 May 2025 19:15:52 UTC

Source modified

17 Jun 2026 09:28:51 UTC

Saved here

25 Oct 2026 02:24:54 UTC

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CVSS 4.0 · [email protected] · Secondary · 8.7 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

### 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. ### Patches The issue has been patched in versions 5.11.3 and 6.1.1. ### 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 using `openpgp.createMessage`) to `openpgp.verify`. - When decrypting and verifying signed+encrypted messages, decrypt and verify the message in two steps, by first calling `openpgp.decrypt` without `verificationKeys`, and then passing the returned signature(s) and a new message containing the decrypted data (created using `openpgp.createMessage`) to `openpgp.verify`. ### Acknowledgements We would like to thank: - Edoardo Geraci and Thomas Rinsma of [Codean Labs](https://codeanlabs.com/) for finding and reporting this vulnerability - The [Sovereign Tech Agency](https://www.sovereign.tech/) for sponsoring the [OpenPGP.js bug bounty program](https://yeswehack.com/programs/openpgp-js-bug-bounty-program) - [YesWeHack](https://www.yeswehack.com/) for hosting the [OpenPGP.js bug bounty program](https://yeswehack.com/programs/openpgp-js-bug-bounty-program)

Source published

19 May 2025 21:54:43 UTC

Source modified

10 Sep 2026 03:50:57 UTC

Saved here

24 Oct 2026 13:17:17 UTC

Source terms

GitHub Advisory Database · CC-BY-4.0

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Source: osv · GitHub Advisory Database · CC-BY-4.0. The publisher's wording is preserved. ChangeIntel groups the information and labels changes. The JSON record includes additional source fields.

CVSS_V4 · CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N

Publisher rating · HIGH