rust-openssl: Incorrect Calculation of Buffer Size
CVE-2026-45784 is a high-severity incorrect calculation of buffer size vulnerability in rust-openssl, with a CVSS 3.1 base score of 7.1 out of 10. It can be exploited with local access to the system by an attacker with a low-privileged account, without any action from a user. Affected rust-openssl versions: >= 0.10.50, < 0.10.80. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.13% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update OpenSSL to 0.10.80 or a later version.
- Read the advisory on github.com for workarounds and exact fixed builds.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Rust-openssl | rust-openssl | >= 0.10.50, < 0.10.80 | Not stated |
| Sfackler | OpenSSL | 0.10.50 up to, but not including, 0.10.80 | 0.10.80 |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- LocalThe attacker needs local access or must trick a user into running something.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- LowA basic user account is enough.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- NoneNo data is disclosed.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 4.0 | 5.1 | Medium | CNA (github.com) |
| CVSS 3.1 | 7.1 | High | NVD |
Official description
rust-openssl provides OpenSSL bindings for the Rust programming language. From 0.10.50 until 0.10.80, CipherCtxRef::cipher_update_inplace in openssl/src/cipher_ctx.rs incorrectly sized output buffers when used with AES key-wrap-with-padding ciphers EVP_aes_{128,192,256}_wrap_pad. For a non-multiple-of-8 input, OpenSSL writes up to 7 bytes past the end of the caller's buffer or Vec, producing attacker-controllable heap corruption when the plaintext length is attacker-influenced. This issue is fixed in version 0.10.80.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Incorrect Calculation of Buffer Size
The product does not correctly calculate the size to be used when allocating a buffer.
How developers prevent this class of flaw
- When allocating a buffer for the purpose of transforming, converting, or encoding an input, allocate enough memory to handle the largest possible encoding. For example, in a routine that converts & characters to & for HTML entity encoding, the output buffer needs to be at least 5 times as large as the input buffer.
- Understand the programming language's underlying representation and how it interacts with numeric calculation (CWE-681). Pay close attention to byte size discrepancies, precision, signed/unsigned distinctions, truncation, conversion and casting between types, not-a-number calculations, and how the language handles numbers that are too large or too small for its underlying representation. Also be careful to account for 32-bit, 64-bit, and other potential differences that may affect the numeric representation.
- Perform input validation on any numeric input by ensuring that it is within the expected range. Enforce that the input meets both the minimum and maximum requirements for the expected range.
More Incorrect Calculation of Buffer Size vulnerabilities (CWE-131)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
Other vulnerabilities in rust-openssl
- 8.7 High severity
- 7.5 High severity
- 8.1 High severity
- 9.1 Critical severity
- 7.5 High severity
Recent Incorrect Calculation of Buffer Size vulnerabilities
- 7.8 High severity
- 8.8 High severity
- 7.2 High severity
- 8.4 High severity
- 7.5 High severity
- 9.3 Critical severity
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