---
cve: "CVE-2026-16000"
severity: "HIGH"
cvss: 8.7
epss: "0.3%"
vendor: "Legion of the Bouncy Castle Inc."
kev: false
exploited: false
published: "2026-10-02 07:16:36"
tags: [cve, security, high]
source: tsecurity.de CVE-Dossier
exported: "2026-10-05T03:13:37+02:00"
---

# CVE-2026-16000

> 8.7 HIGH · 🧪 PoC

## Beschreibung

Missing cryptographic step in the DSTU 7624 CCM mode implementation (KCcmBlockCipher) in Legion of the Bouncy Castle Inc. bc-csharp before 2.7.0 allows an attacker who can observe encrypted messages of known or chosen content to forge ciphertexts with valid authentication tags, via messages encrypted without associated data. The cause is that the G1 block, which binds the nonce, the message length and the parameter flags into the CBC-MAC, was processed only when associated data was present. Without associated data the tag was a CBC-MAC of the plaintext alone, independent of the nonce. Only applications that use KCcmBlockCipher directly and supply no associated data are affected.

## CNA-Record (Kanon, cvelistV5)

- CNA: **bcorg**
- State: PUBLISHED
- Stand: 2026-10-02 18:00:20
- CNA-CVSS: **8.7** (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N`)

## CISA-Anreicherung (vulnrichment/ADP)

- CISA-SSVC (Coordinator, v2.0.3):
  - Exploitation: **none**
  - Automatable: **yes**
  - Technical Impact: **partial**

## CVSS-Vektor

```
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N
```

| Metrik | Wert | Bewertung |
|---|---|---|
| AV Angriffsvektor | Netzwerk | bad |
| AC Komplexität | Gering | bad |
| PR Privilegien | Keine | bad |
| UI Interaktion | Keine | bad |

## Patch verfügbar (OSV)

- 4007498b13582d90ee1eda5d9920c324428b98b3 (Commit)
- b01e9e6c0e231b90867fbaf03bf148bde6f9ccfb (Commit)

## BSI-Hinweise (deutsch)

- [Bouncy Castle: Mehrere Schwachstellen](https://wid.cert-bund.de/portal/wid/sicherheitshinweis/WID-SEC-W-2026-3713) — _BSI-Einstufung: mittel_
  Ein entfernter, anonymer Angreifer kann mehrere Schwachstellen in Bouncy Castle ausnutzen, um Sicherheitsvorkehrungen zu umgehen, Daten zu manipulieren oder offenzulegen und einen Denial-of-Service-Zustand auszulösen.

## Referenzen

- <https://github.com/bcgit/bc-csharp/wiki/CVE-2026-16000>
- <https://github.com/bcgit/bc-csharp/commit/b01e9e6c0e231b90867fbaf03bf148bde6f9ccfb>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2026-16000) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI WID (CSAF)_