CVE-2026-8149 GCM chunking can lead to bad tag exception on decryption
A flaw in Bouncy Castle GCM chunking causes decryption exceptions, potentially leading to denial of service for applications using affected versions.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-8149?
CVE-2026-8149 is a medium-severity denial of service vulnerability in Legion of the Bouncy Castle Inc. BC-FJA, published on 8 May 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
A vulnerability in Legion of the Bouncy Castle Inc. BC-LTS bcprov-lts8on on X86_64, AVX, AVX-512f, Linux, Legion of the Bouncy Castle Inc. BC-FJA bc-fips on Linux, X86_64, AVX, AVX-512f.
This vulnerability is associated with program files gcm128w, gcm512w, gcm128w.C, gcm512w.C.
This issue affects BC-LTS: from 2.73.0 before 2.73.11; BC-FJA: from 2.1.0 before 2.1.3.
Weakness: CWE-1068
Which versions are affected by CVE-2026-8149?
2 open source packages ship an affected version, including org.bouncycastle:bcprov-lts8on.
| Package | Affected | Fixed in |
|---|---|---|
org.bouncycastle:bcprov-lts8on Maven | From 2.73.0 | 2.73.11 |
org.bouncycastle:bcprov-lts8on Maven | From 2.73.0 | 2.73.11 |
How do I fix CVE-2026-8149?
Upgrade org.bouncycastle:bcprov-lts8on to 2.73.11 or later.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-8149 being exploited?
There is no known exploitation of CVE-2026-8149 in the wild and no public exploit code.
Sources
Also known as CLEANSTART-2026-JO17621, GHSA-mx76-r943-rf8g, MINI-3945-g8c4-6wj7.