CVE-2025-65849Public exploitNetwork attack vector

Plaintext recovery via client-visible AES-GCM inputs

Published Dec 8, 2025 · Updated Dec 11, 2025

Cryptanalytic weakness in Altcha obfuscation mode 0.8.0 through 2.2.4 allows remote attackers to recover hidden plaintext and its nonce. The clarifyData function derives an AES-GCM key from a client-visible value and uses the proof-of-work number directly as the initialization vector, exposing relationships that permit constant-time recovery instead of the intended search. The claim applies when the encryption key is shared with the client, including the documented empty-string default; the supplier disputes that bypassing bot deterrence constitutes a security vulnerability.

CVSS severity9.1
Critical
EPSS probability0.22%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Cryptanalytic weakness in Altcha obfuscation mode 0.8.0 through 2.2.4 allows remote attackers to recover hidden plaintext and its nonce. The clarifyData function derives an AES-GCM key from a client-visible value and uses the proof-of-work number directly as the initialization vector, exposing relationships that permit constant-time recovery instead of the intended search. The claim applies when the encryption key is shared with the client, including the documented empty-string default; the supplier disputes that bypassing bot deterrence constitutes a security vulnerability.

The record

CVE
CVE-2025-65849
Published
Dec 8, 2025
Updated
Dec 11, 2025
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-327, T1140
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Dec 8, 2025CVE publishedPublication date reported by the CVE source.
  2. Dec 11, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

9.1CISACVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
5.5GitHubCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:P

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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

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

Weakness, pattern, technique

CWE-327Use of a Broken or Risky Cryptographic Algorithm
T1140Deobfuscate/Decode Files or Information

Public exploit references

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

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo