🛡️ CVE-2023-26154 — c-core
Description
pubnub Insufficient Entropy vulnerability
Versions of the package pubnub before 7.4.0; all versions of the package com.pubnub:pubnub; versions of the package pubnub before 6.19.0; all versions of the package github.com/pubnub/go; versions of the package github.com/pubnub/go/v7 before 7.2.0; versions of the package pubnub before 7.3.0; versions of the package pubnub/pubnub before 6.1.0; versions of the package pubnub before 5.3.0; versions of the package pubnub before 0.4.0; versions of the package pubnub/c-core before 4.5.0; versions of the package com.pubnub:pubnub-kotlin before 7.7.0; versions of the package pubnub/swift before 6.2.0; versions of the package pubnub before 5.2.0; versions of the package pubnub before 4.3.0 are vulnerable to Insufficient Entropy via the getKey function, due to inefficient implementation of the AES-256-CBC cryptographic algorithm. The provided encrypt function is less secure when hex encoding and trimming are applied, leaving half of the bits in the key always the same for every encoded message or file.
Note:
In order to exploit this vulnerability, the attacker needs to invest resources in preparing the attack and brute-force the encryption.
How this vulnerability can be exploited
This issue can be reached over the network, attack complexity is high, an attacker needs no privileges on the target. No user interaction is required. The scope is unchanged, so the impact stays within the vulnerable component. Rated impact: confidentiality high, integrity none, availability none.
CVSS metrics in full
The score comes from this vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
- Attack vector: Network — reachable from anywhere that can route to the service.
- Attack complexity: High — the attacker first has to win a race, learn a secret or otherwise prepare the target.
- Privileges required: None — an unauthenticated stranger can try it.
- User interaction: None — nobody has to be tricked into anything.
- Scope: Unchanged — the damage stays inside the vulnerable component.
- Confidentiality impact: High — total loss, or loss the attacker controls.
- Integrity impact: None.
- Availability impact: None.
Weakness class
CVE-2023-26154 is classified as CWE-331: Insufficient Entropy. A generator is seeded with too little randomness, narrowing the range of outputs an attacker must search.
Affected software
CVE-2023-26154 is recorded against 12 packages.
- c-core (fixed in 4.5.0)
- com.pubnub:pubnub
- com.pubnub:pubnub-kotlin (fixed in 7.7.0)
- github.com/pubnub/go
- github.com/pubnub/go/v5
- github.com/pubnub/go/v6
- github.com/pubnub/go/v7
- github.com/pubnub/swift
- kotlin (fixed in 7.7.0)
- pubnub (fixed in 7.3.0)
- pubnub/pubnub (fixed in 6.1.0)
- swift (fixed in 6.2.0)
Timeline and source
Published on 6 December 2023 and last revised on 17 June 2026. A public exploit is known to exist, which raises the urgency of patching considerably. A vendor advisory or fix has been published. Record sourced from NVD.
References
gist.github.com
github.com
github.com
security.snyk.io
security.snyk.io
security.snyk.io
security.snyk.io
security.snyk.io
security.snyk.io
security.snyk.io
security.snyk.io
security.snyk.io
security.snyk.io
security.snyk.io
security.snyk.io
security.snyk.io
security.snyk.io
gist.github.com
github.com
github.com
security.snyk.io
security.snyk.io
security.snyk.io
security.snyk.io
security.snyk.io
security.snyk.io
security.snyk.io
security.snyk.io
security.snyk.io
security.snyk.io
security.snyk.io
security.snyk.io
security.snyk.io
security.snyk.io
Same weakness in other software
These advisories are the same class of weakness (CWE-331: Insufficient Entropy) in other software:
- CVE-2026-71851 (9.5 Critical, published 7 Aug 2026)
- CVE-2025-15629 (7.5 High, published 3 Aug 2026)
- CVE-2026-38447 (9.8 Critical, published 3 Aug 2026)
- CVE-2026-4932 (4.2 Medium, published 28 Jul 2026)
- CVE-2026-11403 (published 14 Jul 2026)
- CVE-2026-13199 (4.0 Medium, published 7 Jul 2026)
- CVE-2026-4930 (published 25 Jun 2026)
- CVE-2026-7210 (5.0 Medium, published 5 Jun 2026)
Details
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
Affected Packages
| Software | From version | Fixed in |
|---|---|---|
| c-core | — | 4.5.0 |
| com.pubnub:pubnub | — | — |
| com.pubnub:pubnub-kotlin | — | 7.7.0 |
| github.com/pubnub/go | — | — |
| github.com/pubnub/go/v5 | — | — |
| github.com/pubnub/go/v6 | — | — |
| github.com/pubnub/go/v7 | — | — |
| github.com/pubnub/swift | — | — |
| kotlin | — | 7.7.0 |
| pubnub | — | 7.3.0 |
| pubnub/pubnub | — | 6.1.0 |
| swift | — | 6.2.0 |
References
Exploit Protection
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CVE-2023-26154 carries CVSS 5.9 Medium rating and a public exploit already exists. BotEraser checks your installation against this and other known CVE records, and blocks IPs associated with exploit activity.
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