Raw vector
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/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:XSummary
CVE-2026-63091 is a high-severity Buffer Over-read (CWE-126) vulnerability in Proftpd Proftpd. Its CVSS base score is 7.1 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique OS Credential Dumping (T1003); ranked at the 22th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.
The strongest mitigations our analysis identified map to SA-11 (Developer Testing and Evaluation) and SA-8 (Security and Privacy Engineering Principles) — see the control section below for these in your framework.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-45961
Vulnerability Data
ProFTPD before 1.3.9c and 1.3.10rc3 contains a signed integer overflow vulnerability in the mod_sftp module's SCP size-record parser that allows authenticated low-privilege attackers to bypass ASLR by sending a crafted file size value of UINT64_MAX, which results in a negative…
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off_t value. Attackers can exploit the subsequent conversion to uint32_t, causing an approximately 4 GB requested read length and forcing the server to read beyond the end of the SSH channel data and write overread process memory into the uploaded file. In tested configurations, the disclosed data contains libc, libcrypto, and PIE pointers sufficient to derive their randomized base addresses, thereby bypassing ASLR and enabling reliable exploitation of memory corruption vulnerabilities in the same process.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Control response
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V5.2.6
Mitigating Controls (NIST 800-53 r5) AI
Developer testing and evaluation (static analysis, fuzzing, bounds checking tests) directly finds buffer over-read flaws.
Engineering principles such as memory-safe design and bounds-checked abstractions structurally stop introduction of out-of-bounds reads.
Process isolation limits the blast radius of an over-read to the compromised domain.
Input validation enforces length and index constraints that prevent many externally triggered over-reads.
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.
Secure development practices directly prevent introduction of buffer over-read weaknesses.
Vulnerability identification processes can discover buffer over-read flaws via scanning or review.
Patching or replacing vulnerable software removes known instances of buffer over-read bugs.
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.
Security testing in development can detect buffer over-reads before release.
Secure SDLC mandates input validation and bounds checking that can prevent buffer over-reads.
Application security requirements can specify buffer-size and bounds-checking rules.
Secure architecture principles include memory-safety and bounds-checking design choices.
Secure coding standards directly require bounds-checked buffer access, mitigating over-reads.