CVE-2026-87732Public exploit

Unverified plaintext processing via late tag validation

Published Sep 9, 2026 · Updated Sep 9, 2026

Improper verification in OCaml mirage-crypto before 2.2.0 allows local users to place unverified plaintext in output buffers. The affected AES GCM, AES CCM16, and ChaCha20 decrypt-into functions write decrypted data to the destination before validating the AEAD tag. Reachability requires a caller to invoke an affected API with forged input and consume the destination despite a false result, allowing unauthenticated data to enter later processing.

CVSS severity6.2
Medium
EPSS probability0.08%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper verification in OCaml mirage-crypto before 2.2.0 allows local users to place unverified plaintext in output buffers. The affected AES GCM, AES CCM16, and ChaCha20 decrypt-into functions write decrypted data to the destination before validating the AEAD tag. Reachability requires a caller to invoke an affected API with forged input and consume the destination despite a false result, allowing unauthenticated data to enter later processing.

The record

CVE
CVE-2026-87732
Published
Sep 9, 2026
Updated
Sep 9, 2026
Vendor
OCaml
Product
mirage-crypto
Classifications
CWE-347
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 9, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 9, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <2.2.0

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

OCaml · mirage-cryptoversion=0 <2.2.0

Published CVSS scores

6.2OCaml Security AdvisoriesCVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-347Improper Verification of Cryptographic Signature

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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