CVE-2026-63310
Raw vector
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/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:XSummary
CVE-2026-63310 is a critical-severity Download of Code Without Integrity Check (CWE-494) vulnerability. Its CVSS base score is 9.3 (Critical).
Operationally, exploitation aligns with the MITRE ATT&CK technique Supply Chain Compromise (T1195); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-64335
Vulnerability Data
NLTK before 3.9.3 fails to verify file integrity after downloading packages and before extraction in the downloader module. Attackers can perform man-in-the-middle attacks or DNS poisoning to inject malicious package contents that are extracted without validation.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise Techniques
Affected Assets
Mitigating Controls
Control response
—
—
- 9 hardening rules · 5 OS baselines
—
Likely Mitigating Controls AI
Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.
Policies can require integrity verification of software prior to installation, reducing risks from unverified downloads.
Blocks installation of components lacking a valid signature, mitigating download or installation of code without integrity checks.
Acquisition and maintenance portions of the strategy drive requirements for integrity verification of downloaded or supplied code.
Mandating integrity control and approved-only changes during development prevents incorporation of code or components lacking integrity validation.
Supply chain protection requires integrity verification of acquired components, directly reducing insertion or tampering of malicious code during delivery.
Reduces exposure to code obtained without integrity verification by requiring assurance processes that confirm authenticity and absence of tampering.
Tamper resistance and detection commonly include integrity verification of code and firmware obtained from external sources.
Component authenticity requires verifying origin/integrity of acquired firmware or software, directly preventing inclusion of code without 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.
Directly requires assessing authenticity/integrity of software before acquisition and use, preventing unverified downloads.
Requires cryptographic integrity protections (signatures/hashes) for data-in-transit, covering downloaded code.
Prevents execution of unauthorized software, blocking the outcome of an unchecked download.
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.
Mandating integrity checks, digital signatures, and origin tracing for ICT components directly reduces the chance that code or firmware lacking an integrity check will be accepted into the organisation’s environment.
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 (1 rule)
- 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-494
Oracle Linux 9 (1 rule)
- V-271524 OL 9 must check the GPG signature of software packages originating from external software repositories before installation. prevents CWE-494
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-494
- 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-494
RHEL 8 (1 rule)
- 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-494
RHEL 9 (1 rule)
- V-257820 RHEL 9 must check the GPG signature of software packages originating from external software repositories before installation. prevents CWE-494