Cyber Resilience

CVE-2026-75803

Openssl 3.0.0 – 3.0.22

Published
25 August 2026
Modified
11 September 2026
Patch / advisory
View advisory
CVSS Score v3.1 9.1
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
EPSS Score 0.0022 13th percentile
Risk Priority 65 floored blend · peak EPSS

CVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.

Summary

CVE-2026-75803 is a critical-severity Improper Validation of Integrity Check Value (CWE-354) vulnerability in Openssl Openssl. Its CVSS base score is 9.1 (Critical).

Operationally, exploitation aligns with the MITRE ATT&CK technique Supply Chain Compromise (T1195); ranked at the 13th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

The strongest mitigations our analysis identified map to SC-13 (Cryptographic Protection) and SC-8 (Transmission Confidentiality and Integrity) — see the control section below for these in your framework.

EU & UK References

Vulnerability Data

Issue summary: ChaCha20-Poly1305 and AES-OCB decryption with an empty ciphertext can report success without verifying the supplied authentication tag when the operation is finalized by calling the EVP_Cipher() function. Impact summary: Applications calling EVP_Cipher() on an empty ciphertext and expecting…

more

the call to check the AEAD tag may accept forged messages. CWE: CWE-354 (Improper Validation of Integrity Check Value) Description: The EVP_Cipher() API call for AEAD ciphers behaves like a one shot encryption and decryption call. It also verifies the AEAD tag after the decryption operation. However for AES-OCB and ChaCha20-Poly1305 ciphers it skipped the AEAD tag verification when an empty ciphertext was passed to the function. The callers of this function might believe that a successful return indicates a valid AEAD tag for these ciphers, even when that has not truly been validated in this case. FIPS impact: no The FIPS modules in 4.0, 3.6, 3.5, 3.4, and 3.0 are not affected by this CVE as the affected algorithms are not FIPS approved and thus not implemented in the FIPS module.

CWE(s)
CWE-354

Related Threats

MITRE ATT&CK Enterprise Techniques

T1195 Supply Chain Compromise Initial Access
Adversaries may manipulate products or product delivery mechanisms prior to receipt by a final consumer for the purpose of data or system compromise.
attack.mitre.org →
T1195.001 Compromise Software Dependencies and Development Tools Initial Access
Adversaries may manipulate software dependencies and development tools prior to receipt by a final consumer for the purpose of data or system compromise.
attack.mitre.org →
T1195.002 Compromise Software Supply Chain Initial Access
Adversaries may manipulate application software prior to receipt by a final consumer for the purpose of data or system compromise.
attack.mitre.org →
T1542 Pre-OS Boot Stealth
Adversaries may abuse Pre-OS Boot mechanisms as a way to establish persistence on a system.
attack.mitre.org →
T1565 Data Manipulation Impact
Adversaries may insert, delete, or manipulate data in order to influence external outcomes or hide activity, thus threatening the integrity of the data.
attack.mitre.org →
T1565.002 Transmitted Data Manipulation Impact
Adversaries may alter data en route to storage or other systems in order to manipulate external outcomes or hide activity, thus threatening the integrity of the data.
attack.mitre.org →
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2026-34181Same product: Openssl Openssl
CVE-2026-34182Same product: Openssl Openssl
CVE-2026-28390Same product: Openssl Openssl
CVE-2025-15467Same product: Openssl Openssl
CVE-2023-4807Same product: Openssl Openssl
CVE-2023-5678Same product: Openssl Openssl
CVE-2025-69420Same product: Openssl Openssl
CVE-2025-4575Same product: Openssl Openssl
CVE-2026-28386Same product: Openssl Openssl
CVE-2026-45445Same product: Openssl Openssl

Affected Assets

openssl
openssl
3.0.0 — 3.0.22 · 3.4.0 — 3.4.7 · 3.5.0 — 3.5.8

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

—

Detect
Catch it (NIST detect / respond)

—

Harden
Shrink the surface (DISA STIG)
  • 10 hardening rules · 4 OS baselines
Validate
Prove the fix (OWASP ASVS)
  • V10.4.12

Mitigating Controls (NIST 800-53 r5) AI

SI-7 Software, Firmware, and Information Integrity good match

Requires integrity verification tools that detect unauthorized changes when checksum validation is missing or flawed.

SC-13 Cryptographic Protection good match

Mandates cryptographic mechanisms that include integrity protection, preventing improper checksum validation.

SC-8 Transmission Confidentiality and Integrity good match

Requires protection of transmitted information integrity, directly mandating correct validation of integrity checks.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

ID.RA-09 partial match
prevents

Mandates pre-acquisition integrity assessment, addressing only the initial portion of the weakness lifecycle.

PR.DS-01 partial match
prevents

Requires cryptographic hashes and signatures that directly enforce integrity-check validation for data at rest.

PR.DS-02 partial match
prevents

Requires cryptographic hashes and signatures that directly enforce integrity-check validation for data in transit.

RC.RP-03 partial match
prevents

Requires verification of backup integrity, covering validation only within recovery scenarios.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

A.8.24 Use of cryptography partial match
prevents

Cryptographic controls mandate integrity mechanisms whose correct validation directly prevents CWE-354.

A.8.26 Application security requirements partial match
prevents

Application security requirements include integrity checks on messages and data, mitigating improper validation.

A.8.28 Secure coding partial match
prevents

Secure coding standards require proper implementation and validation of checksums or MACs.

A.8.29 Security testing in development and acceptance partial match
finds

Security testing can detect missing integrity validation but does not itself implement the control.

Hardening callouts derived

Configuration rules from DISA STIG baselines that bear on weaknesses of the type cited by this CVE. Each rule is shown with the relationship its mapping actually records, against the CWE it was authored against. Derived via CVE→CWE over `controls_xwalks` (higher-evidence rows only; rows rated `none` are excluded).

Oracle Linux 8 (2 rules)
  • V-248574 YUM must be configured to prevent the installation of patches, service packs, device drivers, or OL 8 system components that have not been digitally signed using a certificate that is recognized and approved by the organization. prevents CWE-354
  • V-248575 OL 8 must prevent the installation of software, patches, service packs, device drivers, or operating system components of local packages without verification they have been digitally signed using a certificate that is issued by a Certificate Authority (CA) that is recognized and approved by the organization. prevents CWE-354
Oracle Linux 9 (1 rule)
  • V-271523 OL 9 must check the GPG signature of locally installed software packages before installation. prevents CWE-354
RHEL 7 (2 rules)
  • V-204447 The Red Hat Enterprise Linux operating system must prevent the installation of software, patches, service packs, device drivers, or operating system components from a repository without verification they have been digitally signed using a certificate that is issued by a Certificate Authority (CA) that is recognized and approved by the organization. prevents CWE-354
  • V-204448 The Red Hat Enterprise Linux operating system must prevent the installation of software, patches, service packs, device drivers, or operating system components of local packages without verification they have been digitally signed using a certificate that is issued by a Certificate Authority (CA) that is recognized and approved by the organization. prevents CWE-354
RHEL 8 (2 rules)
  • V-230264 RHEL 8 must prevent the installation of software, patches, service packs, device drivers, or operating system components from a repository without verification they have been digitally signed using a certificate that is issued by a Certificate Authority (CA) that is recognized and approved by the organization. prevents CWE-354
  • V-230265 RHEL 8 must prevent the installation of software, patches, service packs, device drivers, or operating system components of local packages without verification they have been digitally signed using a certificate that is issued by a Certificate Authority (CA) that is recognized and approved by the organization. prevents CWE-354

References