Vulnerability-Lookup

GHSA-WP5F-6Q39-Q2F4

Vulnerability from github – Published: 2026-08-25 15:32 – Updated: 2026-08-25 15:32

Details

Impact summary: An attacker who supplies a crafted CMS message can trigger a deterministic 8-byte out-of-bounds heap write when the victim decrypts it with CMS_decrypt(), corrupting the heap and typically resulting in a Denial of Service.

CWE: CWE-787: Out-of-bounds Write

Description: The key-wrap OID is potentially attacker-controlled on the wire. CMS unwrapping allows both id-aesNNN-wrap-pad and id-aesNNN-wrap ciphers. An attacker can take a legitimate message and change a single OID byte to select the padded variant while leaving the message otherwise valid. Since the unwrap key is derived from the recipient's private operation (ECDH key agreement or ML-KEM decapsulation), the RFC 5649 integrity check cannot pass, and the decryption fails with integrity failure.

The write is a fixed-size (8-byte), fixed-value (zero) heap overflow immediately past the allocation, requires no special configuration, and is reachable from the public CMS_decrypt() function. The consequence is a heap corruption leading to a Denial of Service. The fix in the CMS code sizes the unwrap output buffer for the worst case so a failed unwrap cannot write past the allocation.

FIPS impact: no

As the CMS code lives outside the FIPS module boundary, no FIPS modules are affected by this CVE.

Severity

7.5 (High)


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

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{
  "affected": [],
  "aliases": [
    "CVE-2026-63072"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-787"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-08-25T13:19:26Z",
    "severity": "HIGH"
  },
  "details": "Issue summary: OpenSSL CMS decryption sizes the key-unwrap output buffer based\non querying the unwrapped key size, but the AES-WRAP-PAD unwrap primitive\ncan write and cleanse more bytes than that query reports, causing an 8-byte\nout-of-bounds heap write.\n\nImpact summary: An attacker who supplies a crafted CMS message can trigger a\ndeterministic 8-byte out-of-bounds heap write when the victim decrypts it\nwith CMS_decrypt(), corrupting the heap and typically resulting in a Denial\nof Service.\n\nCWE: CWE-787: Out-of-bounds Write\n\nDescription: The key-wrap OID is potentially attacker-controlled on the wire.\nCMS unwrapping allows both id-aesNNN-wrap-pad and id-aesNNN-wrap ciphers.\nAn attacker can take a legitimate message and change a single OID byte to\nselect the padded variant while leaving the message otherwise valid. Since\nthe unwrap key is derived from the recipient\u0027s private operation (ECDH key\nagreement or ML-KEM decapsulation), the RFC 5649 integrity check cannot\npass, and the decryption fails with integrity failure.\n\nThe write is a fixed-size (8-byte), fixed-value (zero) heap overflow\nimmediately past the allocation, requires no special configuration, and is\nreachable from the public CMS_decrypt() function. The consequence is\na heap corruption leading to a Denial of Service. The fix in the CMS code\nsizes the unwrap output buffer for the worst case so a failed unwrap cannot\nwrite past the allocation.\n\nFIPS impact: no\n\nAs the CMS code lives outside the FIPS module boundary, no FIPS\nmodules are affected by this CVE.",
  "id": "GHSA-wp5f-6q39-q2f4",
  "modified": "2026-08-25T15:32:59Z",
  "published": "2026-08-25T15:32:58Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-63072"
    },
    {
      "type": "WEB",
      "url": "https://github.com/openssl/openssl/commit/2a3dac874c8057c1f0186849bf1ede1ae7b6b756"
    },
    {
      "type": "WEB",
      "url": "https://github.com/openssl/openssl/commit/87784ad619af36b8807c2044b3940006fccc1e42"
    },
    {
      "type": "WEB",
      "url": "https://github.com/openssl/openssl/commit/9530a5fd1aacaeccdced4478ea2340a480613335"
    },
    {
      "type": "WEB",
      "url": "https://github.com/openssl/openssl/commit/9ec2f6d2ae2bcad907cf7ee38584855bafe4979a"
    },
    {
      "type": "WEB",
      "url": "https://github.com/openssl/openssl/commit/a0c8ec557d9cac078f032d76cdf684fe743eb382"
    },
    {
      "type": "WEB",
      "url": "https://openssl-library.org/news/secadv/20260825.txt"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    }
  ]
}

CVE-2026-63072 (GCVE-0-2026-63072)

Vulnerability from cvelistv5 – Published: 2026-08-25 12:59 – Updated: 2026-08-25 14:29

Title

Heap Buffer Overflow in CMS Key Unwrapping

Summary

Issue summary: OpenSSL CMS decryption sizes the key-unwrap output buffer based on querying the unwrapped key size, but the AES-WRAP-PAD unwrap primitive can write and cleanse more bytes than that query reports, causing an 8-byte out-of-bounds heap write. Impact summary: An attacker who supplies a crafted CMS message can trigger a deterministic 8-byte out-of-bounds heap write when the victim decrypts it with CMS_decrypt(), corrupting the heap and typically resulting in a Denial of Service. CWE: CWE-787: Out-of-bounds Write Description: The key-wrap OID is potentially attacker-controlled on the wire. CMS unwrapping allows both id-aesNNN-wrap-pad and id-aesNNN-wrap ciphers. An attacker can take a legitimate message and change a single OID byte to select the padded variant while leaving the message otherwise valid. Since the unwrap key is derived from the recipient's private operation (ECDH key agreement or ML-KEM decapsulation), the RFC 5649 integrity check cannot pass, and the decryption fails with integrity failure. The write is a fixed-size (8-byte), fixed-value (zero) heap overflow immediately past the allocation, requires no special configuration, and is reachable from the public CMS_decrypt() function. The consequence is a heap corruption leading to a Denial of Service. The fix in the CMS code sizes the unwrap output buffer for the worst case so a failed unwrap cannot write past the allocation. FIPS impact: no As the CMS code lives outside the FIPS module boundary, no FIPS modules are affected by this CVE.

Severity

7.5 (High)


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

SSVC

Exploitation: none Automatable: yes Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-08-25 14:29 UTC

CWE

CWE-787 - Out-of-bounds Write

Assigner

openssl mitre root

References

6 references

URL	Tags
https://openssl-library.org/news/secadv/20260825.txt	vendor-advisory
https://github.com/openssl/openssl/commit/9530a5f…	patch
https://github.com/openssl/openssl/commit/2a3dac8…	patch
https://github.com/openssl/openssl/commit/87784ad…	patch
https://github.com/openssl/openssl/commit/9ec2f6d…	patch
https://github.com/openssl/openssl/commit/a0c8ec5…	patch

Impacted products

1 product

Vendor	Product	Version
OpenSSL	OpenSSL	Affected: 4.0.0 , < 4.0.2 (semver) Affected: 3.6.0 , < 3.6.4 (semver) Affected: 3.5.0 , < 3.5.8 (semver) Affected: 3.4.0 , < 3.4.7 (semver) Affected: 3.0.0 , < 3.0.22 (semver) Affected: 1.1.1 , < 1.1.1zi (custom)

Date Public

2026-08-25 11:36

Credits

Bhabani Sankar Das Filipe Casal(Trail of Bits) Daniel Kubec

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              "attackComplexity": "LOW",
              "attackVector": "NETWORK",
              "availabilityImpact": "HIGH",
              "baseScore": 7.5,
              "baseSeverity": "HIGH",
              "confidentialityImpact": "NONE",
              "integrityImpact": "NONE",
              "privilegesRequired": "NONE",
              "scope": "UNCHANGED",
              "userInteraction": "NONE",
              "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
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                "timestamp": "2026-08-25T14:29:50.344129Z",
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          "dateUpdated": "2026-08-25T14:29:55.378Z",
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              "status": "affected",
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              "value": "Issue summary: OpenSSL CMS decryption sizes the key-unwrap output buffer based\u003cbr\u003eon querying the unwrapped key size, but the AES-WRAP-PAD unwrap primitive\u003cbr\u003ecan write and cleanse more bytes than that query reports, causing an 8-byte\u003cbr\u003eout-of-bounds heap write.\u003cbr\u003e\u003cbr\u003eImpact summary: An attacker who supplies a crafted CMS message can trigger a\u003cbr\u003edeterministic 8-byte out-of-bounds heap write when the victim decrypts it\u003cbr\u003ewith CMS_decrypt(), corrupting the heap and typically resulting in a Denial\u003cbr\u003eof Service.\u003cbr\u003e\u003cbr\u003eCWE: CWE-787: Out-of-bounds Write\u003cbr\u003e\u003cbr\u003eDescription: The key-wrap OID is potentially attacker-controlled on the wire.\u003cbr\u003eCMS unwrapping allows both id-aesNNN-wrap-pad and id-aesNNN-wrap ciphers.\u003cbr\u003eAn attacker can take a legitimate message and change a single OID byte to\u003cbr\u003eselect the padded variant while leaving the message otherwise valid. Since\u003cbr\u003ethe unwrap key is derived from the recipient\u0027s private operation (ECDH key\u003cbr\u003eagreement or ML-KEM decapsulation), the RFC 5649 integrity check cannot\u003cbr\u003epass, and the decryption fails with integrity failure.\u003cbr\u003e\u003cbr\u003eThe write is a fixed-size (8-byte), fixed-value (zero) heap overflow\u003cbr\u003eimmediately past the allocation, requires no special configuration, and is\u003cbr\u003ereachable from the public CMS_decrypt() function. The consequence is\u003cbr\u003ea heap corruption leading to a Denial of Service. The fix in the CMS code\u003cbr\u003esizes the unwrap output buffer for the worst case so a failed unwrap cannot\u003cbr\u003ewrite past the allocation.\u003cbr\u003e\u003cbr\u003eFIPS impact: no\u003cbr\u003e\u003cbr\u003eAs the CMS code lives outside the FIPS module boundary, no FIPS\u003cbr\u003emodules are affected by this CVE."
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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.

Detection rules are retrieved from Rulezet.

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.

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GHSA-WP5F-6Q39-Q2F4

CVE-2026-63072 (GCVE-0-2026-63072)

Tags

Sightings

Nomenclature