Sequoia PGP has Subtraction Overflow when aes_key_unwrap function is provided ciphertext that is too shortGHSA-v6x3-9r38-r27q
MEDIUMGHSA-v6x3-9r38-r27q is a medium-severity (CVSS 5.3) CWE-195 vulnerability in sequoia-openpgp. A fix is available for sequoia-openpgp — see the affected versions and patch details below.
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 GHSA-v6x3-9r38-r27q.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
Where this sits among everything scored
Real-World Exposure
sequoia-openpgpReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects crates.io packages — download data is not available via public APIs for these ecosystems.
Description
In Sequoia before 2.1.0, aes_key_unwrap panics if passed a ciphertext that is too short. A remote attacker can take advantage of this issue to crash an application by sending a victim an encrypted message with a crafted PKESK or SKESK packet.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🦀crates.io | sequoia-openpgp | all versions | 2.1.0cargo update -p sequoia-openpgp --precise 2.1.0 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for sequoia-openpgp, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update sequoia-openpgp to 2.1.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-v6x3-9r38-r27q 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.
Fixing This On Your OS
If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.
This vulnerability is rated Moderate for Red Hat. A remote attacker could crash an application using Sequoia by sending a specially crafted encrypted message. Successful exploitation requires high attack complexity and user interaction, as the victim must process the malicious message.
Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.Source: Red Hat security advisory for GHSA-v6x3-9r38-r27q (CC BY 4.0)
Frequently Asked Questions
Is GHSA-v6x3-9r38-r27q in your dependencies?
Find it across crates.io, including transitive dependencies.