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CVE-2026-63072 on Cyberus Linux 26.05

Aliases: CVE-2026-63072

Packages: openssl, openssl_3_6

Status: Resolved

Advisory Information

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.

Updates

2026-09-21 21:58 CEST

Metadata changes:

  • Status for package openssl: “Resolved” (acb9af0383a5591b4860b43718b210d562c5e52a)
  • Status for package openssl_3_6: “Resolved” (acb9af0383a5591b4860b43718b210d562c5e52a)

2026-09-09 19:22 CEST

Metadata changes:

  • Status for package openssl_3: “Resolved” (acb9af0383a5591b4860b43718b210d562c5e52a)
  • Status for package openssl_3_5: “Resolved” (acb9af0383a5591b4860b43718b210d562c5e52a)
  • Status for package openssl_4_0: “Resolved” (acb9af0383a5591b4860b43718b210d562c5e52a)

(Amended on: 2026-09-21 21:57 CEST)

2026-09-09 19:22 CEST

Metadata changes:

  • Status for package openssl: “In Progress” (9c945e4a5e4b2a997b6ca4e2aba881234ca27855)
  • Status for package openssl_3_6: “In Progress” (9c945e4a5e4b2a997b6ca4e2aba881234ca27855)

2026-08-25 17:38 CEST

Metadata changes:

  • Status for package openssl_3: “Plausible”
  • Status for package openssl_3_5: “Plausible”
  • Status for package openssl_3_6: “Plausible”
  • Status for package openssl_4_0: “Plausible”

2026-08-25 17:36 CEST

Metadata changes:

  • Status for package openssl_3: “New”
  • Status for package openssl_3_5: “New”
  • Status for package openssl_3_6: “New”
  • Status for package openssl_4_0: “New”