CVE-2026-77696

Impact summary: An attacker able to measure SM2 signing times may learn information about the per-signature secret nonce, which over many signatures can, via a lattice / Hidden Number Problem attack, lead to recovery of the private key.

CWE: CWE-208: Observable Timing Discrepancy

Description: SM2 signature generation computes the signature value using variable-time BIGNUM operations on the secret nonce and the private key, so the time taken to produce an SM2 signature depends on these secret values, forming a timing side-channel.

Applications performing SM2 signature generation are affected on all platforms.

FIPS Impact: no SM2 is not a FIPS algorithm.

Database specific

{
    "cna_assigner": "openssl",
    "cwe_ids": [
        "CWE-208"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/77xxx/CVE-2026-77696.json",
    "unresolved_ranges": [
        {
            "extracted_events": [
                {
                    "introduced": "3.0.0"
                },
                {
                    "fixed": "3.0.23"
                }
            ],
            "source": "AFFECTED_FIELD"
        }
    ]
}

References

Affected packages

Git / github.com/openssl/openssl

Affected ranges

Type

GIT

Repo

https://github.com/openssl/openssl

Events

Introduced

11b7b6ea3b65a584e1d31408ed1bdb139465cffd

Fixed

af1775b60dfa141a4ad762585052cabeb9f37e9e

Introduced

7b371d80d959ec9ab4139d09d78e83c090de9779

Fixed

c8bd5a57108599ac650bbae77fcabe3109dab2e8

Introduced

636dfadc70ce26f2473870570bfd9ec352806b1d

Fixed

45e844fa2a14ec92d146bd8f5778ac130b6625fb

Introduced

98acb6b02839c609ef5b837794e08d906d965335

Fixed

e72c946f6f6d94c8ba5119acb25340b7b6b2073f

Introduced

e04bd3433fd84e1861bf258ea37928d9845e6a86

Fixed

e04bd3433fd84e1861bf258ea37928d9845e6a86

Database specific

Show details

{
    "extracted_events": [
        {
            "introduced": "4.0.0"
        },
        {
            "fixed": "4.0.3"
        },
        {
            "introduced": "3.6.0"
        },
        {
            "fixed": "3.6.5"
        },
        {
            "introduced": "3.5.0"
        },
        {
            "fixed": "3.5.9"
        },
        {
            "introduced": "3.4.0"
        },
        {
            "fixed": "3.4.8"
        },
        {
            "introduced": "1.1.1"
        },
        {
            "fixed": "1.1.1zj"
        }
    ],
    "source": "AFFECTED_FIELD"
}

Affected versions

3.*

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-3.4.0

openssl-3.4.1

openssl-3.4.2

openssl-3.4.3

openssl-3.4.4

openssl-3.4.5

openssl-3.4.6

openssl-3.4.7

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-3.5.6

openssl-3.5.7

openssl-3.5.8

openssl-3.6.0

openssl-3.6.1

openssl-3.6.2

openssl-3.6.3

openssl-3.6.4

openssl-4.*

openssl-4.0.0

openssl-4.0.1

openssl-4.0.2

Database specific

source

"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2026-77696.json"

vanir_signatures

[
    {
        "deprecated": false,
        "digest": {
            "line_hashes": [
                "28170854778703993674264004058177114599",
                "73132526844288570625317440636111911761",
                "177405411499435185068645597737938634778",
                "224809958623850711330610094965797758930",
                "295554444428855106393106961197201359586"
            ],
            "threshold": 0.9
        },
        "id": "CVE-2026-77696-c377fa22",
        "signature_type": "Line",
        "signature_version": "v1",
        "source": "https://github.com/openssl/openssl/commit/e04bd3433fd84e1861bf258ea37928d9845e6a86",
        "target": {
            "file": "include/openssl/opensslv.h"
        }
    }
]

vanir_signatures_modified

"2026-09-30T08:16:02Z"