{"answers":{"affected":"It affects 1 product.","exploited":"There is no known exploitation of CVE-2026-66035 in the wild and no public exploit code.","fix":"Apply the vendor's patch.","what":"CVE-2026-66035 is a high-severity memory corruption vulnerability in libssh2, published on 24 Jul 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link."},"fix_prompt":"Check this codebase for CVE-2026-66035 and fix it if it is affected.\n\nWhat it is: CVE-2026-66035 is a high-severity memory corruption vulnerability in libssh2, published on 24 Jul 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.\nExploitation: There is no known exploitation of CVE-2026-66035 in the wild and no public exploit code.\n\nAffected product: libssh2. No package-level version data is available, so check the vendor advisory linked from the reference page.\n\nTask:\n1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.\n2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.\n3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.\n4. Run the tests and summarise what changed and why.\n5. If nothing in the project is affected, say so and change nothing.\n\nReference: https://insights.sbomify.com/CVE-2026-66035/ (Markdown: https://insights.sbomify.com/CVE-2026-66035/index.md)","id":"CVE-2026-66035","markdown":"https://insights.sbomify.com/CVE-2026-66035/index.md","name":"CVE-2026-66035","record":{"aliases":["ALPINE-CVE-2026-66035","AZL-93399","BELL-CVE-2026-66035","DEBIAN-CVE-2026-66035","ECHO-a13b-3527-8590","GHSA-v6rf-8q4r-r495","JLSEC-2026-1088","RHSA-2026:46955","ROOT-OS-DEBIAN-11-CVE-2026-66035","UBUNTU-CVE-2026-66035"],"analysis":{"component_type":"library","fix_type":"patch","impacts":["code_execution"],"network_reachable":"yes","non_default_config":false,"product_category":"SSH client library","requires_auth":"none","summary":"A malicious SSH server can trigger a heap buffer overflow in libssh2 clients during handshake, potentially leading to remote code execution.","user_interaction":"required","vuln_class":"memory_corruption"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"VulnCheck","cpe":[{"product":"libssh2","vendor":"libssh2"}],"cvss":{"score":7.7,"severity":"high","source":"cna","vector":"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","version":"4.0"},"cwes":[{"id":"CWE-122","name":"Heap-based Buffer Overflow"}],"description":"libssh2 through 1.11.1, fixed in commit 42e33d8, contains a pre-authentication heap buffer overflow vulnerability that allows a malicious SSH server to corrupt heap metadata in any connecting client by sending a packet with a packet_length smaller than the cipher's block size during Encrypt-then-MAC cipher negotiation. In the fullpacket() function in src/transport.c, the ETM path allocates a buffer of packet_length bytes but copies blocksize minus one bytes via memcpy, causing an overflow that on 32-bit glibc writes attacker-controlled bytes into an adjacent chunk's SIZE field, enabling tcache bin confusion, overlapping live objects, and function pointer overwrite during the session handshake before authentication.","ecosystems":["Red Hat:hummingbird:1"],"exploits":{"exploitdb":0,"first_seen":null,"github_poc":0,"max_poc_stars":null,"metasploit":0,"nuclei":0,"refs":[],"tier":"none_known"},"has_fix":true,"headline":"libssh2 Heap Buffer Overflow via ETM Cipher Negotiation","id":"CVE-2026-66035","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":null,"product":null,"products":[],"type":"memory_corruption","year":"2026"},"n_packages":3,"n_references":3,"next":{"headline":"FFmpeg Heap Out-of-Bounds Write in vf_hqdn3d Filter","id":"CVE-2026-66036"},"packages":[{"ecosystem":"Red Hat:hummingbird:1","fixed":["0:1.11.1-10.3.hum1"],"introduced":["0"],"last_affected":[],"package":"libssh2","purl":"pkg:rpm/redhat/libssh2","source":"RHSA-2026:46955"},{"ecosystem":"Red Hat:hummingbird:1","fixed":["0:1.11.1-10.3.hum1"],"introduced":["0"],"last_affected":[],"package":"libssh2-devel","purl":"pkg:rpm/redhat/libssh2-devel","source":"RHSA-2026:46955"},{"ecosystem":"Red Hat:hummingbird:1","fixed":["0:1.11.1-10.3.hum1"],"introduced":["0"],"last_affected":[],"package":"libssh2-docs","purl":"pkg:rpm/redhat/libssh2-docs","source":"RHSA-2026:46955"}],"prev":{"headline":"libssh2 Heap Out-of-Bounds Read via publickey subsystem","id":"CVE-2026-66034"},"products":["libssh2"],"published":"2026-07-24","related":[{"cvss_score":9.2,"headline":"libssh2 - Out-of-Bounds Write via Unchecked packet_length in transport.c","id":"CVE-2026-55200","kev_date_added":null,"published":"2026-06-17"},{"cvss_score":8.7,"headline":"libssh2 Double-Free Heap Corruption via sftp_open()","id":"CVE-2026-66032","kev_date_added":null,"published":"2026-07-24"},{"cvss_score":8.7,"headline":"libssh2 Integer Underflow DoS via AES-GCM Cipher Negotiation","id":"CVE-2026-66033","kev_date_added":null,"published":"2026-07-24"},{"cvss_score":8.3,"headline":"libssh2 - Integer Overflow in publickey Subsystem Attribute Allocation","id":"CVE-2026-58050","kev_date_added":null,"published":"2026-06-28"},{"cvss_score":8.3,"headline":"libssh2 - Free of Uninitialized Pointer in publickey List Cleanup","id":"CVE-2026-58051","kev_date_added":null,"published":"2026-06-28"},{"cvss_score":8.3,"headline":"libssh2 - Heap Buffer Over-read via sftp_symlink() in sftp.c","id":"CVE-2025-15661","kev_date_added":null,"published":"2026-06-18"},{"cvss_score":8.2,"headline":"libssh2 - Pre-Authentication DoS via SSH_MSG_EXT_INFO Handler","id":"CVE-2026-55199","kev_date_added":null,"published":"2026-06-17"}],"sources":[{"class":"attribution","licence":"CVE Terms of Use (MITRE)","name":"CVE List","prefix":"CVE"},{"class":"attribution","licence":"CC BY 4.0","name":"Red Hat","prefix":"RHSA"},{"class":"attribution","licence":"US public information, NVD API terms","name":"NVD"},{"class":"attribution","licence":"CWE Terms of Use","name":"CWE (MITRE)"},{"class":"attribution","licence":"FIRST CVSS licence","name":"CVSS (FIRST)"}],"ssvc":{"automatable":"no","exploitation":"none","technical_impact":"total"},"state":"PUBLISHED","updated":"2026-07-28","vendors":["libssh2"]},"summary":"A malicious SSH server can trigger a heap buffer overflow in libssh2 clients during handshake, potentially leading to remote code execution.","url":"https://insights.sbomify.com/CVE-2026-66035/"}