CVE-2019-9153

Message Signature Bypass in openpgp

7.5 HighPublic exploitFix available

Improper Verification of a Cryptographic Signature in OpenPGP.js <=4.1.2 allows an attacker to forge signed messages by replacing its signatures with a "standalone" or "timestamp" signature.

Attack profile

How easy it is to exploit

Attack vector: Network
Complexity: Low
Privileges needed: None
User interaction: None

What an attacker can affect

Confidentiality: None
Integrity: High
Availability: None

Exploit likelihood

2.01%Up 0.6 points since Apr 14, 2021

What each source reports

NVD Score used 7.5

Improper Verification of a Cryptographic Signature in OpenPGP.js <=4.1.2 allows an attacker to forge signed messages by replacing its signatures with a "standalone" or "timestamp" signature.

Record: CVE-2019-9153
CVSS 3.0: 7.5 HighCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
CVSS 2.0: 5.0 MediumAV:N/AC:L/Au:N/C:N/I:P/A:N
Weakness: CWE-347
Updated: 2026-11-02

CVE List No score

Improper Verification of a Cryptographic Signature in OpenPGP.js <=4.1.2 allows an attacker to forge signed messages by replacing its signatures with a "standalone" or "timestamp" signature.

Record: CVE-2019-9153
Updated: 2026-11-02

EUVDEUVD-2019-0640 No score

Improper Verification of a Cryptographic Signature in OpenPGP.js <=4.1.2 allows an attacker to forge signed messages by replacing its signatures with a "standalone" or "timestamp" signature.

Record: EUVD-2019-0640
Updated: 2026-11-03

GitHub AdvisoriesGHSA-qwqc-28w3-fww6 7.5

Message Signature Bypass in openpgp

Versions of openpgp prior to 4.2.0 are vulnerable to Message Signature Bypass. The package fails to verify that a message signature is of type text. This allows an attacker to to construct a message with a signature type that only verifies subpackets without additional input (such as standalone or timestamp). For example, an attacker that captures a standalone signature packet from a victim can construct arbitrary signed messages that would be verified correctly.

Recommendation

Upgrade to version 4.2.0 or later. If you are upgrading from a version <4.0.0 it is highly recommended to read the High-Level API Changes section of the openpgp 4.0.0 release: https://github.com/openpgpjs/openpgpjs/releases/tag/v4.0.0

Record: GHSA-qwqc-28w3-fww6
CVSS 3.0: 7.5 HighCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
Weakness: CWE-347
Updated: 2026-11-02

OSV 7.5

Improper Verification of a Cryptographic Signature in OpenPGP.js <=4.1.2 allows an attacker to forge signed messages by replacing its signatures with a "standalone" or "timestamp" signature.

Record: CVE-2019-9153
CVSS 3.0: 7.5 HighCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
Updated: 2026-11-02

OSVGHSA-qwqc-28w3-fww6 7.5

Message Signature Bypass in openpgp

Recommendation

Record: GHSA-qwqc-28w3-fww6
CVSS 3.0: 7.5 HighCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
Weakness: CWE-347
Updated: 2026-11-02

Affected products

openpgpjs

Affected packages

Affected packages
Package	Affected	Fixed
`openpgp` npm	through 4.1.2	4.2.0
`openpgp` npm	before 4.2.0	4.2.0

Public exploits

Links only. Every CVE stores no exploit code.

Public exploits
Source	Link	Date
PoC in GitHub	ZenyWay/opgp-service-cve-2019-9153	2019-09-11

History

History
Recorded	Changed	Sources
Nov 3, 2026	aliases	EUVD
Nov 2, 2026	first indexed	CVE List, GitHub Advisories, NVD, OSV, PoC in GitHub

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2019-9153 is a high vulnerability (CVSS 7.5) in Openpgpjs, published August 22, 2019. Public exploit code exists. EPSS puts the chance of exploitation in the next 30 days at 2.01%, the 80th percentile. Fixed in openpgp 4.2.0.

References

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