{"id":"JLSEC-2026-1087","summary":"libssh2 through 1.11.1, fixed in commit a13bb6c, contains a missing bounds check vulnerability...","details":"libssh2 through 1.11.1, fixed in commit a13bb6c, contains a missing bounds check vulnerability that allows a malicious SSH server to trigger an arbitrary-length heap out-of-bounds read and a free of an uninitialized pointer via the publickey subsystem. In `libssh2_publickey_list_fetch()`, the version 1 response parser reads a server-controlled `comment_len` value and advances the parse pointer without verifying sufficient bytes remain in the buffer, causing the out-of-bounds read to leak heap pointers from adjacent allocations defeating ASLR, followed by heap allocator state corruption when the error cleanup path frees an uninitialized pointer from a non-zeroed realloc() region.","modified":"2026-07-31T18:20:51.695941143Z","published":"2026-07-31T18:09:08.751Z","upstream":["CVE-2026-66034","EUVD-2026-48721","GHSA-6h6q-9mwg-r6x7"],"database_specific":{"sources":[{"database_specific":{"status":"Analyzed"},"id":"CVE-2026-66034","imported":"2026-07-31T17:07:21.951Z","modified":"2026-07-30T15:44:38.170Z","published":"2026-07-24T17:17:35.407Z","url":"https://services.nvd.nist.gov/rest/json/cves/2.0?cveId=CVE-2026-66034","html_url":"https://nvd.nist.gov/vuln/detail/CVE-2026-66034"},{"id":"GHSA-6h6q-9mwg-r6x7","imported":"2026-07-31T17:07:27.607Z","modified":"2026-07-24T18:31:30Z","published":"2026-07-24T18:31:30Z","url":"https://api.github.com/advisories/GHSA-6h6q-9mwg-r6x7","html_url":"https://github.com/advisories/GHSA-6h6q-9mwg-r6x7"},{"url":"https://euvdservices.enisa.europa.eu/api/enisaid?id=EUVD-2026-48721","html_url":"https://euvd.enisa.europa.eu/vulnerability/EUVD-2026-48721","id":"EUVD-2026-48721","imported":"2026-07-31T17:07:23.723Z","modified":"2026-07-28T01:06:26Z","published":"2026-07-24T16:42:18Z"}],"license":"CC-BY-4.0"},"references":[{"type":"WEB","url":"https://github.com/advisories/GHSA-6h6q-9mwg-r6x7"},{"type":"WEB","url":"https://github.com/libssh2/libssh2/commit/a13bb6c773f0d55ad1628cede57e99803cd898d9"},{"type":"WEB","url":"https://github.com/libssh2/libssh2/pull/2202"},{"type":"WEB","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-66034"},{"type":"WEB","url":"https://www.vulncheck.com/advisories/libssh2-heap-out-of-bounds-read-via-publickey-subsystem"}],"affected":[{"package":{"name":"LibSSH2_jll","ecosystem":"Julia","purl":"pkg:julia/LibSSH2_jll?uuid=29816b5a-b9ab-546f-933c-edad1886dfa8"},"ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"1.11.104+0"}]}],"database_specific":{"source":"https://github.com/JuliaLang/SecurityAdvisories.jl/tree/generated/osv/2026/JLSEC-2026-1087.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H"},{"type":"CVSS_V4","score":"CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:P/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:X"}]}