The version of OpenSSL installed on the remote host is prior to 3.5.6. It is, therefore, affected by multiple vulnerabilities as referenced in the 3.5.6 advisory.

  - Issue summary: An OpenSSL TLS 1.3 server may fail to negotiate the expected preferred key exchange group     when its key exchange group configuration includes the default by using the 'DEFAULT' keyword. Impact     summary: A less preferred key exchange may be used even when a more preferred group is supported by both     client and server, if the group was not included among the client's initial predicated keyshares. This     will sometimes be the case with the new hybrid post-quantum groups, if the client chooses to defer their     use until specifically requested by the server. If an OpenSSL TLS 1.3 server's configuration uses the     'DEFAULT' keyword to interpolate the built-in default group list into its own configuration, perhaps     adding or removing specific elements, then an implementation defect causes the 'DEFAULT' list to lose its     'tuple' structure, and all server-supported groups were treated as a single sufficiently secure 'tuple',     with the server not sending a Hello Retry Request (HRR) even when a group in a more preferred tuple was     mutually supported. As a result, the client and server might fail to negotiate a mutually supported post-     quantum key agreement group, such as 'X25519MLKEM768', if the client's configuration results in only     'classical' groups (such as 'X25519' being the only ones in the client's initial keyshare prediction).
    OpenSSL 3.5 and later support a new syntax for selecting the most preferred TLS 1.3 key agreement group on     TLS servers. The old syntax had a single 'flat' list of groups, and treated all the supported groups as     sufficiently secure. If any of the keyshares predicted by the client were supported by the server the most     preferred among these was selected, even if other groups supported by the client, but not included in the     list of predicted keyshares would have been more preferred, if included. The new syntax partitions the     groups into distinct 'tuples' of roughly equivalent security. Within each tuple the most preferred group     included among the client's predicted keyshares is chosen, but if the client supports a group from a more     preferred tuple, but did not predict any corresponding keyshares, the server will ask the client to retry     the ClientHello (by issuing a Hello Retry Request or HRR) with the most preferred mutually supported     group. The above works as expected when the server's configuration uses the built-in default group list,     or explicitly defines its own list by directly defining the various desired groups and group 'tuples'. No     OpenSSL FIPS modules are affected by this issue, the code in question lies outside the FIPS boundary.
    OpenSSL 3.6 and 3.5 are vulnerable to this issue. OpenSSL 3.6 users should upgrade to OpenSSL 3.6.2 once     it is released. OpenSSL 3.5 users should upgrade to OpenSSL 3.5.6 once it is released. OpenSSL 3.4, 3.3,     3.0, 1.0.2 and 1.1.1 are not affected by this issue. (CVE-2026-2673)

  - 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.  RSA_public_encrypt() 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 EVP_PKEY_encapsulate() 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 EVP_PKEY_public_check() or EVP_PKEY_public_check_quick() before EVP_PKEY_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.
    Fixed in OpenSSL 3.0.20 (Affected since 3.0.0). (CVE-2026-31790)

  - Issue summary: Converting an excessively large OCTET STRING value to a hexadecimal string leads to a heap     buffer overflow on 32 bit platforms.  Impact summary: A heap buffer overflow may lead to a crash or     possibly an attacker controlled code execution or other undefined behavior.  If an attacker can supply a     crafted X.509 certificate with an excessively large OCTET STRING value in extensions such as the Subject     Key Identifier (SKID) or Authority Key Identifier (AKID) which are being converted to hex, the size of the     buffer needed for the result is calculated as multiplication of the input length by 3. On 32 bit     platforms, this multiplication may overflow resulting in the allocation of a smaller buffer and a heap     buffer overflow.  Applications and services that print or log contents of untrusted X.509 certificates are     vulnerable to this issue. As the certificates would have to have sizes of over 1 Gigabyte, printing or     logging such certificates is a fairly unlikely operation and only 32 bit platforms are affected, this     issue was assigned Low severity.  The FIPS modules in 3.6, 3.5, 3.4, 3.3 and 3.0 are not affected by this     issue, as the affected code is outside the OpenSSL FIPS module boundary. Fixed in OpenSSL 3.0.20 (Affected     since 3.0.0). (CVE-2026-31789)

  - Issue summary: During processing of a crafted CMS EnvelopedData message with KeyTransportRecipientInfo a     NULL pointer dereference can happen.  Impact summary: Applications that process attacker-controlled CMS     data may crash before authentication or cryptographic operations occur resulting in Denial of Service.
    When a CMS EnvelopedData message that uses KeyTransportRecipientInfo with RSA-OAEP encryption is     processed, the optional parameters field of RSA-OAEP SourceFunc algorithm identifier is examined without     checking for its presence. This results in a NULL pointer dereference if the field is missing.
    Applications and services that call CMS_decrypt() on untrusted input (e.g., S/MIME processing or CMS-based     protocols) are vulnerable.  The FIPS modules in 3.6, 3.5, 3.4, 3.3 and 3.0 are not affected by this issue,     as the affected code is outside the OpenSSL FIPS module boundary. Fixed in OpenSSL 1.1.1zg (Affected since     1.1.1). (CVE-2026-28390)

  - Issue summary: During processing of a crafted CMS EnvelopedData message with KeyAgreeRecipientInfo a NULL     pointer dereference can happen.  Impact summary: Applications that process attacker-controlled CMS data     may crash before authentication or cryptographic operations occur resulting in Denial of Service.  When a     CMS EnvelopedData message that uses KeyAgreeRecipientInfo is processed, the optional parameters field of     KeyEncryptionAlgorithmIdentifier is examined without checking for its presence. This results in a NULL     pointer dereference if the field is missing.  Applications and services that call CMS_decrypt() on     untrusted input (e.g., S/MIME processing or CMS-based protocols) are vulnerable.  The FIPS modules in 3.6,     3.5, 3.4, 3.3 and 3.0 are not affected by this issue, as the affected code is outside the OpenSSL FIPS     module boundary. Fixed in OpenSSL 1.1.1zg (Affected since 1.1.1). (CVE-2026-28389)

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

Detections

Analytics

OpenSSL 3.5.0 < 3.5.6 Multiple Vulnerabilities

high Nessus Plugin ID 302500

Version 1.5

Version 1.4

Version 1.3

Version 1.2

Version 1.1

Version 1.5 Apr 14, 2026, 9:52 AM CVSSv3 score source (set to "CVE-2026-31790") Plugin Feed: 202604140952
Version 1.4 Apr 10, 2026, 7:42 PM Plugin metadata (Add IAVM Info) Plugin Feed: 202604101942
Version 1.3 Apr 8, 2026, 12:46 AM Plugin metadata CVE (set "CVE" coverage to "CVE-2026-2673,CVE-2026-28387,CVE-2026-28388,CVE-2026-28389,CVE-2026-28390,CVE-2026-31789,CVE-2026-31790") CVSS metrics ("CVSSv2 score" set to 7.8) CVSS metrics ("CVSSv2 vector" set to "CVSS2#AV:N/AC:L/Au:N/C:C/I:N/A:N") Plugin Feed: 202604080046
Version 1.2 Mar 18, 2026, 10:57 AM CVSS metrics ("CVSSv3 score" set to 7.5) CVSS metrics ("CVSSv3 vector" set to "CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N") Plugin Feed: 202603181057
Version 1.1 Mar 17, 2026, 4:16 PM New Plugin Feed: 202603171616