Vulnerability · Published Aug 3, 2026 · Assigned by bcorg

CVE-2026-13506Lazy ASN.1 sequence forcing resets nesting-depth guard

High 8.7

In plain English

A high-severity security flaw in BC-FJA from Legion of the Bouncy Castle Inc.. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 43% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 4.0)8.7High
Exploit odds (30 days)0.5%top 57.4% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official description

In Bouncy Castle for Java before 1.85, Lazy ASN.1 sequence forcing resets nesting-depth guard. This issue also affects Bouncy Castle for Java LTS before 2.73.12, and Bouncy Castle for Java FIPS (BC-FJA) before bc-fips 1.0.2.7 (1.0.X series), 2.0.2 (2.0.X series) and 2.1.3 (2.1.X series).

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Debian:12bouncycastleno fix listedDEBIAN-CVE-2026-13506
Debian:13bouncycastleno fix listedDEBIAN-CVE-2026-13506
Debian:14bouncycastle1.86-1DEBIAN-CVE-2026-13506
Mavenorg.bouncycastle:bc-fips2.1.3GHSA-qp49-qgx5-5m26
Mavenorg.bouncycastle:bc-fips1.0.2.7GHSA-qp49-qgx5-5m26
Mavenorg.bouncycastle:bc-fips2.0.2GHSA-qp49-qgx5-5m26
Mavenorg.bouncycastle:bcprov-jdk15to181.85GHSA-qp49-qgx5-5m26
Mavenorg.bouncycastle:bcprov-jdk18on1.85GHSA-qp49-qgx5-5m26
Mavenorg.bouncycastle:bcprov-lts8on2.73.12GHSA-qp49-qgx5-5m26
Ubuntu:26.04:LTSbouncycastleno fix listedUBUNTU-CVE-2026-13506
Ubuntu:26.10bouncycastleno fix listedUBUNTU-CVE-2026-13506

Affected products (as reported)

VendorProductVersions
Legion of the Bouncy Castle Inc. BC-JAVA 0 – before 1.85
Legion of the Bouncy Castle Inc. BC-LTS-JAVA 2.73.0 – before 2.73.12
Legion of the Bouncy Castle Inc. BC-FJA 1.0.0 – before 1.0.2.72.0.0 – before 2.0.22.1.0 – before 2.1.3

Weakness: CWE-674 · Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/U:Amber

References