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PatchSiren cyber security CVE debrief

CVE-2026-89086 OCaml CVE debrief

AI-assisted PatchSiren debrief based on the supplied source corpus. The CVE record was published on 2026-09-10T20:17:32.113Z and has not been modified since then. The jose package before 0.11.0 for OCaml has a vulnerability where library calls to validate an RSA signature only confirm that PKCS #1 decoding succeeds, and proceed to declare the signature valid without the required steps that involve the public key. Defenders responsible for OCaml applications using the jose package should assess exposure and prioritize verification and potential upgrades. The vulnerability requires verification of the jose package version and potential upgrades to 0.11.0 or later. OCaml application

Vendor
OCaml
Product
jose
CVSS
CRITICAL 9.1
CISA KEV
Not listed in stored evidence
Original CVE published
2026-09-10
Original CVE updated
2026-09-22
Advisory published
2026-09-10
Advisory updated
2026-09-22

Who should care

Defenders responsible for OCaml applications using the jose package should assess exposure and prioritize verification and potential upgrades.

Why it matters

Defenders should care about CVE-2026-89086 because it affects the jose package in OCaml, potentially allowing invalid RSA signatures to be declared valid. This vulnerability requires verification of the jose package version and potential upgrades to 0.11.0 or later. OCaml application defenders and developers should assess exposure and prioritize verification and remediation efforts.

  • Potential for invalid RSA signatures to be accepted as valid
  • Need for verification of jose package version and potential upgrades
  • Possible impact on cryptographic validation procedures in dependent applications

Technical summary

The jose package before 0.11.0 for OCaml has a vulnerability where library calls to validate an RSA signature only confirm that PKCS #1 decoding succeeds, and proceed to declare the signature valid without the required steps that involve the public key.

Defensive priority

Defenders should prioritize verifying the jose package version and upgrading to 0.11.0 or later if using an affected version.

Recommended defensive actions

  • Verify the jose package version and upgrade to 0.11.0 or later if necessary
  • Review and update cryptographic validation procedures to ensure proper public key usage
  • Monitor for potential signature validation issues in dependent applications

Evidence notes

The CVE record and NVD entry provide limited information about the vulnerability. Further verification is required to determine the affected versions and potential impact.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-89086 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-89086

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-89086 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-89086

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.