CVE-2025-9230

Issue summary: An application trying to decrypt CMS messages encrypted using password based encryption can trigger an out-of-bounds read and write.

Impact summary: This out-of-bounds read may trigger a crash which leads to Denial of Service for an application. The out-of-bounds write can cause a memory corruption which can have various consequences including a Denial of Service or Execution of attacker-supplied code.

Although the consequences of a successful exploit of this vulnerability could be severe, the probability that the attacker would be able to perform it is low. Besides, password based (PWRI) encryption support in CMS messages is very rarely used. For that reason the issue was assessed as Moderate severity according to our Security Policy.

The FIPS modules in 3.5, 3.4, 3.3, 3.2, 3.1 and 3.0 are not affected by this issue, as the CMS implementation is outside the OpenSSL FIPS module boundary.

Weakness

The product reads data past the end, or before the beginning, of the intended buffer.

Affected Software

Potential Mitigations

• Assume all input is malicious. Use an “accept known good” input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does.
• When performing input validation, consider all potentially relevant properties, including length, type of input, the full range of acceptable values, missing or extra inputs, syntax, consistency across related fields, and conformance to business rules. As an example of business rule logic, “boat” may be syntactically valid because it only contains alphanumeric characters, but it is not valid if the input is only expected to contain colors such as “red” or “blue.”
• Do not rely exclusively on looking for malicious or malformed inputs. This is likely to miss at least one undesirable input, especially if the code’s environment changes. This can give attackers enough room to bypass the intended validation. However, denylists can be useful for detecting potential attacks or determining which inputs are so malformed that they should be rejected outright.
• To reduce the likelihood of introducing an out-of-bounds read, ensure that you validate and ensure correct calculations for any length argument, buffer size calculation, or offset. Be especially careful of relying on a sentinel (i.e. special character such as NUL) in untrusted inputs.

Related Attack Patterns

• https://cwe.mitre.org/data/definitions/540.html

References

• https://github.com/openssl/openssl/commit/5965ea5dd6960f36d8b7f74f8eac67a8eb8f2b45
• https://github.com/openssl/openssl/commit/9e91358f365dee6c446dcdcdb01c04d2743fd280
• https://github.com/openssl/openssl/commit/a79c4ce559c6a3a8fd4109e9f33c1185d5bf2def
• https://github.com/openssl/openssl/commit/b5282d677551afda7d20e9c00e09561b547b2dfd
• https://github.com/openssl/openssl/commit/bae259a211ada6315dc50900686daaaaaa55f482
• https://github.openssl.org/openssl/extended-releases/commit/c2b96348bfa662f25f4fabf81958ae822063dae3
• https://github.openssl.org/openssl/extended-releases/commit/dfbaf161d8dafc1132dd88cd48ad990ed9b4c8ba
• https://openssl-library.org/news/secadv/20250930.txt