{"answers":{"affected":"It affects 1 product.","exploited":"There is no known exploitation of CVE-2026-66033 in the wild and no public exploit code.","fix":"Apply the vendor's patch.","what":"CVE-2026-66033 is a high-severity vulnerability in libssh2, published on 24 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim."},"fix_prompt":"Check this codebase for CVE-2026-66033 and fix it if it is affected.\n\nWhat it is: CVE-2026-66033 is a high-severity vulnerability in libssh2, published on 24 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.\nExploitation: There is no known exploitation of CVE-2026-66033 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-2026-66033/ (Markdown: https://insights.sbomify.com/CVE-2026-66033/index.md)","id":"CVE-2026-66033","markdown":"https://insights.sbomify.com/CVE-2026-66033/index.md","name":"CVE-2026-66033","record":{"aliases":["ALPINE-CVE-2026-66033","AZL-93402","AZL-97428","BELL-CVE-2026-66033","DEBIAN-CVE-2026-66033","ECHO-bd2e-2758-1b23","GHSA-2g8c-wcg8-r65c","JLSEC-2026-1086","ROOT-OS-DEBIAN-11-CVE-2026-66033","UBUNTU-CVE-2026-66033"],"analysis":{"component_type":"library","fix_type":"patch","impacts":["denial_of_service"],"network_reachable":"yes","non_default_config":false,"product_category":"SSH client library","requires_auth":"none","summary":"A malicious SSH server can crash connecting clients by exploiting an integer underflow in libssh2 during AES-GCM cipher negotiation.","user_interaction":"not_required","vuln_class":"integer_overflow"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"VulnCheck","cpe":[{"product":"libssh2","vendor":"libssh2"}],"cvss":{"score":8.7,"severity":"high","source":"cna","vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N","version":"4.0"},"cwes":[{"id":"CWE-191","name":"Integer Underflow (Wrap or Wraparound)"},{"id":"CWE-125","name":"Out-of-bounds Read"}],"description":"libssh2 through 1.11.1, fixed in commit a2ed82d, contains a pre-authentication integer underflow vulnerability in the ssh2_cipher_crypt() function in src/openssl.c that allows a malicious SSH server to crash any connecting client by negotiating AES-GCM ciphers during handshake. Attackers can exploit the underflow in the expression computing blocksize minus aadlen minus authentication tag length to trigger an out-of-bounds read and a memcpy call with a near-SIZE_MAX length argument, causing immediate process crash before any authentication occurs.","ecosystems":[],"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 Integer Underflow DoS via AES-GCM Cipher Negotiation","id":"CVE-2026-66033","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":null,"product":null,"products":[],"type":"integer_overflow","year":"2026"},"n_packages":0,"n_references":3,"next":{"headline":"libssh2 Heap Out-of-Bounds Read via publickey subsystem","id":"CVE-2026-66034"},"packages":[],"prev":{"headline":"libssh2 Double-Free Heap Corruption via sftp_open()","id":"CVE-2026-66032"},"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":8.3,"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":"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":"yes","exploitation":"none","technical_impact":"partial"},"state":"PUBLISHED","updated":"2026-07-28","vendors":["libssh2"]},"summary":"A malicious SSH server can crash connecting clients by exploiting an integer underflow in libssh2 during AES-GCM cipher negotiation.","url":"https://insights.sbomify.com/CVE-2026-66033/"}