{"cve":"CVE-2026-63091","nvd":{"published":"2026-07-20T15:16:45.363","modified":"2026-07-30T17:18:19.600","status":"Analyzed","description":"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 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.","cvss_v4":{"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","score":7.1},"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N","score":6.5},"cwes":["CWE-126","CWE-190"],"references":["https://github.com/proftpd/proftpd/blob/master/RELEASE_NOTES","https://github.com/proftpd/proftpd/commit/b9b7dde1bcd74bc23366484d53856b67b8d6d95e","https://github.com/proftpd/proftpd/pull/2201","https://github.com/proftpd/proftpd/releases/tag/v1.3.10rc3-3","https://github.com/proftpd/proftpd/releases/tag/v1.3.9c"],"products":["proftpd:proftpd"],"source":"nvd","synced_at":"2026-10-19T22:45:36.895656543+00:00"},"epss":{"cve":"CVE-2026-63091","score":0.00525,"percentile":0.44525,"date":"2026-10-31"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}