Vulnerability-Lookup

GHSA-RV5H-5M9V-CCWC

Vulnerability from github – Published: 2026-09-29 18:31 – Updated: 2026-09-29 18:31

Details

Impact summary: An attacker able to measure 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: The generic elliptic-curve scalar multiplication used for curves that do not have a dedicated constant-time implementation pads the secret scalar with non-constant-time BIGNUM operations, so the time taken depends on the value of the secret scalar derived from the ECDSA and SM2 nonce.

The leak is very small; observing it requires a large number of measurements. The effect is largest for curves whose group order lies on a machine-word boundary, such as brainpoolP384r1.

Applications using ECDSA signing over the Brainpool and other generic prime curves, and SM2 signing on platforms that use the generic implementation, are vulnerable to this issue.

The NIST curves P-256, P-384 and P-521 use dedicated constant-time implementations and are not affected.

FIPS Impact: no The FIPS modules are not affected: the approved NIST curves used in the FIPS provider have dedicated constant-time implementations and do not use the affected code path.

Severity

3.7 (Low)


                  
                    CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N

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{
  "affected": [],
  "aliases": [
    "CVE-2026-54872"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-208"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-09-29T16:17:08Z",
    "severity": "LOW"
  },
  "details": "Issue summary: The generic elliptic-curve scalar multiplication used for\nECDSA and SM2 signature operations with curves that do not have a dedicated\nimplementation leaks information about the secret nonce through timing.\n\nImpact summary: An attacker able to measure signing times may learn\ninformation about the per-signature secret nonce, which over many signatures\ncan, via a lattice / Hidden Number Problem attack, lead to recovery of the\nprivate key.\n\nCWE: CWE-208: Observable Timing Discrepancy\n\nDescription: The generic elliptic-curve scalar multiplication used for\ncurves that do not have a dedicated constant-time implementation pads the\nsecret scalar with non-constant-time BIGNUM operations, so the time taken\ndepends on the value of the secret scalar derived from the ECDSA and SM2 nonce.\n\nThe leak is very small; observing it requires a large number of\nmeasurements. The effect is largest for curves whose group order lies\non a machine-word boundary, such as brainpoolP384r1.\n\nApplications using ECDSA signing over the Brainpool and other generic prime\ncurves, and SM2 signing on platforms that use the generic implementation,\nare vulnerable to this issue.\n\nThe NIST curves P-256, P-384 and P-521 use dedicated constant-time\nimplementations and are not affected.\n\nFIPS Impact: no\nThe FIPS modules are not affected: the approved NIST curves used in the FIPS\nprovider have dedicated constant-time implementations and do not use the\naffected code path.",
  "id": "GHSA-rv5h-5m9v-ccwc",
  "modified": "2026-09-29T18:31:44Z",
  "published": "2026-09-29T18:31:44Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-54872"
    },
    {
      "type": "WEB",
      "url": "https://github.com/openssl/openssl/commit/1a5bee8dc57430a2be69cd1ffe7fec6a62f4f179"
    },
    {
      "type": "WEB",
      "url": "https://github.com/openssl/openssl/commit/3f7e1363dccec6f7732bb9e9fa471bb6e4aa68cb"
    },
    {
      "type": "WEB",
      "url": "https://github.com/openssl/openssl/commit/7d83bc7764999dfd91b83b4f0815b45390422afd"
    },
    {
      "type": "WEB",
      "url": "https://github.com/openssl/openssl/commit/8166827a78aad164a07aa86dea2b425403ced471"
    },
    {
      "type": "WEB",
      "url": "https://openssl-library.org/news/secadv/20260929.txt"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N",
      "type": "CVSS_V3"
    }
  ]
}

CVE-2026-54872 (GCVE-0-2026-54872)

Vulnerability from cvelistv5 – Published: 2026-09-29 15:32 – Updated: 2026-09-29 17:28

Title

Timing Side-Channel in Scalar Multiplication for Non-NIST EC Curves

Summary

Issue summary: The generic elliptic-curve scalar multiplication used for ECDSA and SM2 signature operations with curves that do not have a dedicated implementation leaks information about the secret nonce through timing. Impact summary: An attacker able to measure 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: The generic elliptic-curve scalar multiplication used for curves that do not have a dedicated constant-time implementation pads the secret scalar with non-constant-time BIGNUM operations, so the time taken depends on the value of the secret scalar derived from the ECDSA and SM2 nonce. The leak is very small; observing it requires a large number of measurements. The effect is largest for curves whose group order lies on a machine-word boundary, such as brainpoolP384r1. Applications using ECDSA signing over the Brainpool and other generic prime curves, and SM2 signing on platforms that use the generic implementation, are vulnerable to this issue. The NIST curves P-256, P-384 and P-521 use dedicated constant-time implementations and are not affected. FIPS Impact: no The FIPS modules are not affected: the approved NIST curves used in the FIPS provider have dedicated constant-time implementations and do not use the affected code path.

Severity

3.7 (Low)


                        
                          CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N

SSVC

Exploitation: none Automatable: no Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-09-29 17:27 UTC

CWE

CWE-208 - Observable Timing Discrepancy

Assigner

openssl mitre root Scorecard

References

5 references

URL	Tags
https://openssl-library.org/news/secadv/20260929.txt	vendor-advisory
https://github.com/openssl/openssl/commit/8166827…	patch
https://github.com/openssl/openssl/commit/1a5bee8…	patch
https://github.com/openssl/openssl/commit/3f7e136…	patch
https://github.com/openssl/openssl/commit/7d83bc7…	patch

Impacted products

1 product

Vendor	Product	Version
OpenSSL	OpenSSL	Affected: 4.0.0 , < 4.0.3 (semver) Affected: 3.6.0 , < 3.6.5 (semver) Affected: 3.5.0 , < 3.5.9 (semver) Affected: 3.4.0 , < 3.4.8 (semver) Affected: 3.0.0 , < 3.0.23 (semver) Affected: 1.1.1 , < 1.1.1zj (custom) Affected: 1.0.2 , < 1.0.2zs (custom)

Date Public

2026-09-29 14:21

Credits

Igor Ustinov

Show details on NVD website

JSON

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      {
        "metrics": [
          {
            "cvssV3_1": {
              "attackComplexity": "HIGH",
              "attackVector": "NETWORK",
              "availabilityImpact": "NONE",
              "baseScore": 3.7,
              "baseSeverity": "LOW",
              "confidentialityImpact": "LOW",
              "integrityImpact": "NONE",
              "privilegesRequired": "NONE",
              "scope": "UNCHANGED",
              "userInteraction": "NONE",
              "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N",
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                "id": "CVE-2026-54872",
                "options": [
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                    "Technical Impact": "partial"
                  }
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                "role": "CISA Coordinator",
                "timestamp": "2026-09-29T17:27:46.959054Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-09-29T17:28:12.657Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
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          "defaultStatus": "unaffected",
          "product": "OpenSSL",
          "vendor": "OpenSSL",
          "versions": [
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              "lessThan": "4.0.3",
              "status": "affected",
              "version": "4.0.0",
              "versionType": "semver"
            },
            {
              "lessThan": "3.6.5",
              "status": "affected",
              "version": "3.6.0",
              "versionType": "semver"
            },
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      "credits": [
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      "datePublic": "2026-09-29T14:21:57.000Z",
      "descriptions": [
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          "name": "3.4.8 git commit",
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Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.

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GHSA-RV5H-5M9V-CCWC

CVE-2026-54872 (GCVE-0-2026-54872)

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