CVE-2023-23928: reason-jose is a JOSE implementation in ReasonML and OCaml.`Jose.Jws.validate` does not check HS256 signatures

Q: How do I fix CVE-2023-23928?

reason-jose: upgrade to 0.8.2. Exact commands for each OS are on this page.

Q: Is CVE-2023-23928 being exploited?

CVE-2023-23928 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2023-23928 affect?

CVE-2023-23928 affects reason-jose. Severity is medium (CVSS 5.9). reason-jose is a JOSE implementation in ReasonML and OCaml.`Jose.Jws.validate` does not check HS256 signatures. This allows tampering of JWS header and payload data if the service does not perform additional checks. Such tampering could exp

Q: How urgent is CVE-2023-23928?

Priority 31/100. No elevated risk signals yet.

Routine

MEDIUM 5.9UPGRADE

CVE-2023-23928 is a medium-severity flaw (CVSS 5.9) affecting reason-jose. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

reason-jose is a JOSE implementation in ReasonML and OCaml.`Jose.Jws.validate` does not check HS256 signatures. This allows tampering of JWS header and payload data if the service does not perform additional checks. Such tampering could expose applications using reason-jose to authorization bypass. Applications relying on JWS claims assertion to enforce security boundaries may be vulnerable to privilege escalation. This issue has been patched in

Why this priority

No elevated risk signals yet

A fixed release or distro patch exists.

Risk facts

CVSS score	5.9 (Medium)
Attack vector	Network (remote)
Attack complexity	High
Privileges needed	Low
User interaction	None
EPSS exploit chance	0.5% (top 60%)
CISA exploited list	No
Weakness	CWE-347
Published	2023-02-01
Last modified	2026-06-17

Publisher (CNA): GitHub, Inc. · Vendor: reason-jose project

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2023-02-01 01:15 UTCPublished CVE record published
2026-06-17 05:38 UTCUpdated Record last modified

reason-jose project reason-jose UPGRADE

Affected: < 0.8.2

Fixed in: 0.8.2

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy reason-jose || rpm -q reason-jose || reason-jose --version

2. UPGRADE to 0.8.2 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade reason-jose

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade reason-jose

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2023-23928?

reason-jose: upgrade to 0.8.2. Exact commands for each OS are on this page.

Is CVE-2023-23928 being exploited?

CVE-2023-23928 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2023-23928 affect?

CVE-2023-23928 affects reason-jose. Severity is medium (CVSS 5.9). reason-jose is a JOSE implementation in ReasonML and OCaml.`Jose.Jws.validate` does not check HS256 signatures. This allows tampering of JWS header and payload data if the service does not perform additional checks. Such tampering could exp

How urgent is CVE-2023-23928?

Priority 31/100. No elevated risk signals yet.

References

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