CVE-2026-31790

Issue summary: Applications using RSASVE key encapsulation to establish a secret encryption key can send contents of an uninitialized memory buffer to a malicious peer.

Impact summary: The uninitialized buffer might contain sensitive data from the previous execution of the application process which leads to sensitive data leakage to an attacker.

RSApublicencrypt() returns the number of bytes written on success and -1 on error. The affected code tests only whether the return value is non-zero. As a result, if RSA encryption fails, encapsulation can still return success to the caller, set the output lengths, and leave the caller to use the contents of the ciphertext buffer as if a valid KEM ciphertext had been produced.

If applications use EVPPKEYencapsulate() with RSA/RSASVE on an attacker-supplied invalid RSA public key without first validating that key, then this may cause stale or uninitialized contents of the caller-provided ciphertext buffer to be disclosed to the attacker in place of the KEM ciphertext.

As a workaround calling EVPPKEYpubliccheck() or EVPPKEYpubliccheckquick() before EVPPKEY_encapsulate() will mitigate the issue.

The FIPS modules in 3.6, 3.5, 3.4, 3.3, 3.1 and 3.0 are affected by this issue.

Database specific

{
    "cna_assigner": "openssl",
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/31xxx/CVE-2026-31790.json",
    "cwe_ids": [
        "CWE-754"
    ]
}

References

Affected packages

Git / github.com/openssl/openssl

Affected ranges

Type

GIT

Repo

https://github.com/openssl/openssl

Events

Introduced

7b371d80d959ec9ab4139d09d78e83c090de9779

Fixed

fe686e15d84334b284f883118ed92f64b409b3aa

Introduced

636dfadc70ce26f2473870570bfd9ec352806b1d

Fixed

286ddeaac037533bbdce65b3c689e3f7ffebf0f6

Introduced

98acb6b02839c609ef5b837794e08d906d965335

Fixed

03b8620d6e9b7b4d5701865edb6ad86101fe5517

Introduced

4cb31128b5790819dfeea2739fbde265f71a10a2

Fixed

204165c1550d3aa0f49395af654124cec2bbabf9

Introduced

89cd17a031e022211684eb7eb41190cf1910f9fa

Fixed

5aada9c299a3b28fc82348f4e2b93805fa0a0e9c

Database specific

{
    "extracted_events": [
        {
            "introduced": "3.6.0"
        },
        {
            "fixed": "3.6.2"
        },
        {
            "introduced": "3.5.0"
        },
        {
            "fixed": "3.5.6"
        },
        {
            "introduced": "3.4.0"
        },
        {
            "fixed": "3.4.5"
        },
        {
            "introduced": "3.3.0"
        },
        {
            "fixed": "3.3.7"
        },
        {
            "introduced": "3.0.0"
        },
        {
            "fixed": "3.0.20"
        }
    ],
    "source": "AFFECTED_FIELD"
}

Affected versions

3.*

3.0-POST-CLANG-FORMAT-WEBKIT

3.0-PRE-CLANG-FORMAT-WEBKIT

3.3-POST-CLANG-FORMAT-WEBKIT

3.3-PRE-CLANG-FORMAT-WEBKIT

3.4-POST-CLANG-FORMAT-WEBKIT

3.4-PRE-CLANG-FORMAT-WEBKIT

3.5-POST-CLANG-FORMAT-WEBKIT

3.5-PRE-CLANG-FORMAT-WEBKIT

3.6-POST-CLANG-FORMAT-WEBKIT

3.6-PRE-CLANG-FORMAT-WEBKIT

openssl-3.*

openssl-3.0.0

openssl-3.0.1

openssl-3.0.10

openssl-3.0.11

openssl-3.0.12

openssl-3.0.13

openssl-3.0.14

openssl-3.0.15

openssl-3.0.16

openssl-3.0.17

openssl-3.0.18

openssl-3.0.19

openssl-3.0.2

openssl-3.0.3

openssl-3.0.4

openssl-3.0.5

openssl-3.0.6

openssl-3.0.7

openssl-3.0.8

openssl-3.0.9

openssl-3.3.0

openssl-3.3.1

openssl-3.3.2

openssl-3.3.3

openssl-3.3.4

openssl-3.3.5

openssl-3.3.6

openssl-3.4.0

openssl-3.4.1

openssl-3.4.2

openssl-3.4.3

openssl-3.4.4

openssl-3.5.0

openssl-3.5.1

openssl-3.5.2

openssl-3.5.3

openssl-3.5.4

openssl-3.5.5

openssl-3.6.0

openssl-3.6.1

Database specific

source

"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2026-31790.json"