Cyber Resilience

CVE-2026-8720

Wolfssl 5.9.0 – 5.9.2

Published
25 June 2026
Modified
27 June 2026
Patch / advisory
CVSS Score v4 5.9
Click a component to see what it means
Raw vectorCVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
EPSS Score 0.0011 2th percentile
Risk Priority 29 floored blend · peak EPSS

Summary

CVE-2026-8720 is a medium-severity Improper Validation of Integrity Check Value (CWE-354) vulnerability in Wolfssl Wolfssl. Its CVSS base score is 5.9 (Medium).

Operationally, exploitation aligns with the MITRE ATT&CK technique Supply Chain Compromise (T1195); ranked at the 2th 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

wc_Blake2bHmacFinal and wc_Blake2sHmacFinal discard the message when the key length exceeds the block size, producing a MAC that is independent of the input. When the supplied key is longer than the BLAKE2 block size the key-hashing branch reinitialized the running…

more

hash state, discarding the accumulated message data, so the resulting MAC depended only on the key and not on the message being authenticated. This bug is specific to the HMAC-BLAKE2 APIs that were added in wolfSSL version 5.9.0.

CWE(s)

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.
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.
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.
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.
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.
T1601 Modify System Image Defense Impairment
Adversaries may make changes to the operating system of embedded network devices to weaken defenses and provide new capabilities for themselves.
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2026-6329Same product: Wolfssl Wolfssl
CVE-2026-7511Same product: Wolfssl Wolfssl
CVE-2026-55961Same product: Wolfssl Wolfssl
CVE-2026-6331Same product: Wolfssl Wolfssl
CVE-2026-5503Same product: Wolfssl Wolfssl
CVE-2026-10512Same product: Wolfssl Wolfssl
CVE-2024-1544Same product: Wolfssl Wolfssl
CVE-2026-55960Same product: Wolfssl Wolfssl
CVE-2026-6679Same product: Wolfssl Wolfssl
CVE-2025-7394Same product: Wolfssl Wolfssl

Affected Assets

wolfssl
wolfssl
5.9.0 — 5.9.2

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

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

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

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.

PR.DS-01 mostly match
prevents

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

PR.DS-02 mostly match
prevents

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

ID.RA-09 partial match
prevents

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

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.

prevents

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

prevents

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

finds

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

prevents

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

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` (authoritative 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