CVE-2026-63574: CWE-789 Memory Allocation with Excessive Size Value in Legion of the Bouncy Castle Inc. bc-csharp
Memory allocation with excessive size value in the OpenPGP signature and user attribute subpacket parsers (SignatureSubpacketsParser.ReadPacket, UserAttributeSubpacketsParser.ReadPacket) in Legion of the Bouncy Castle Inc. bc-csharp before 2.7.0 allows a remote, unauthenticated attacker who can supply a crafted OpenPGP public key, certificate or signature to cause a denial of service (OutOfMemoryException or memory exhaustion in the parsing process) via a subpacket header using the five-octet length form, because the declared length was used to size the subpacket buffer with no upper bound and without being compared with the size of the enclosing subpacket area or packet, so a few bytes of input could demand an allocation of up to about 2 GB before any subpacket data was read.
AI Analysis
Technical Summary
The vulnerability exists in the SignatureSubpacketsParser.ReadPacket and UserAttributeSubpacketsParser.ReadPacket functions of bc-csharp before 2.7.0. When parsing OpenPGP data, the code reads a subpacket header that uses a five-octet length form to size the buffer for the subpacket. The declared length is used directly without checking if it exceeds the enclosing subpacket or packet size, allowing a crafted input to request a very large memory allocation (up to about 2 GB) before any subpacket data is processed. This can cause the application to run out of memory and crash, resulting in a denial of service. The vulnerability is remotely exploitable without authentication by supplying malicious OpenPGP data.
Potential Impact
A remote, unauthenticated attacker can cause a denial of service on applications using vulnerable versions of bc-csharp by supplying specially crafted OpenPGP public keys, certificates, or signatures. The attack leads to excessive memory allocation attempts, potentially causing OutOfMemoryException or memory exhaustion during parsing. There is no indication of code execution or data leakage from the provided information.
Mitigation Recommendations
A fix is available in bc-csharp version 2.7.0 and later. Users should upgrade to version 2.7.0 or newer to remediate this vulnerability. No other mitigation or temporary workaround is indicated in the provided data.
CVE-2026-63574: CWE-789 Memory Allocation with Excessive Size Value in Legion of the Bouncy Castle Inc. bc-csharp
Description
Memory allocation with excessive size value in the OpenPGP signature and user attribute subpacket parsers (SignatureSubpacketsParser.ReadPacket, UserAttributeSubpacketsParser.ReadPacket) in Legion of the Bouncy Castle Inc. bc-csharp before 2.7.0 allows a remote, unauthenticated attacker who can supply a crafted OpenPGP public key, certificate or signature to cause a denial of service (OutOfMemoryException or memory exhaustion in the parsing process) via a subpacket header using the five-octet length form, because the declared length was used to size the subpacket buffer with no upper bound and without being compared with the size of the enclosing subpacket area or packet, so a few bytes of input could demand an allocation of up to about 2 GB before any subpacket data was read.
CVSS v4.0
Score 8.7high
Affected software
Legion of the Bouncy Castle Inc.
bc-csharp
pkg:nuget/BouncyCastle.CryptographyRun on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The vulnerability exists in the SignatureSubpacketsParser.ReadPacket and UserAttributeSubpacketsParser.ReadPacket functions of bc-csharp before 2.7.0. When parsing OpenPGP data, the code reads a subpacket header that uses a five-octet length form to size the buffer for the subpacket. The declared length is used directly without checking if it exceeds the enclosing subpacket or packet size, allowing a crafted input to request a very large memory allocation (up to about 2 GB) before any subpacket data is processed. This can cause the application to run out of memory and crash, resulting in a denial of service. The vulnerability is remotely exploitable without authentication by supplying malicious OpenPGP data.
Potential Impact
A remote, unauthenticated attacker can cause a denial of service on applications using vulnerable versions of bc-csharp by supplying specially crafted OpenPGP public keys, certificates, or signatures. The attack leads to excessive memory allocation attempts, potentially causing OutOfMemoryException or memory exhaustion during parsing. There is no indication of code execution or data leakage from the provided information.
Mitigation Recommendations
A fix is available in bc-csharp version 2.7.0 and later. Users should upgrade to version 2.7.0 or newer to remediate this vulnerability. No other mitigation or temporary workaround is indicated in the provided data.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- bcorg
- Date Reserved
- 2026-07-16T23:50:45.118Z
- Cvss Version
- 4.0
- State
- PUBLISHED
Threat ID: 6abf5de7a43b0b3b8988eaae
Added to database: 10/02/2026, 07:31:51 UTC
Last enriched: 10/02/2026, 07:46:21 UTC
Last updated: 10/02/2026, 21:45:56 UTC
Views: 13
Community Reviews
0 reviewsCrowdsource mitigation strategies, share intel context, and vote on the most helpful responses. Sign in to add your voice and help keep defenders ahead.
Want to contribute mitigation steps or threat intel context? Sign in or create an account to join the community discussion.
Actions
Updates to AI analysis require Pro Console access. Upgrade inside Console → Billing.
Need more coverage?
Upgrade to Pro Console for AI refresh and higher limits.
For incident response and remediation, OffSeq services can help resolve threats faster.
Latest Threats
Check if your credentials are on the dark web
Instant breach scanning across billions of leaked records. Free tier available.