JLSEC-2026-1088

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Source

https://github.com/JuliaLang/SecurityAdvisories.jl/blob/main/advisories/published/2026/JLSEC-2026-1088.md

Import Source

https://github.com/JuliaLang/SecurityAdvisories.jl/tree/generated/osv/2026/JLSEC-2026-1088.json

JSON Data

https://api.osv.dev/v1/vulns/JLSEC-2026-1088

Upstream

CVE-2026-66035

EUVD-2026-48722

GHSA-v6rf-8q4r-r495

Published

2026-07-31T18:09:08Z

Modified

2026-07-31T18:20:49Z

Severity

7.5 (High) CVSS_V3 - CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H CVSS Calculator
7.7 (High) CVSS_V4 - 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 CVSS Calculator

Summary

libssh2 through 1.11.1, fixed in commit 42e33d8, contains a pre-authentication heap buffer...

Details

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.

Database specific

{
    "license": "CC-BY-4.0",
    "sources": [
        {
            "database_specific": {
                "status": "Analyzed"
            },
            "html_url": "https://nvd.nist.gov/vuln/detail/CVE-2026-66035",
            "id": "CVE-2026-66035",
            "imported": "2026-07-31T17:07:21.975Z",
            "modified": "2026-07-30T15:41:05.690Z",
            "published": "2026-07-24T17:17:35.547Z",
            "url": "https://services.nvd.nist.gov/rest/json/cves/2.0?cveId=CVE-2026-66035"
        },
        {
            "html_url": "https://github.com/advisories/GHSA-v6rf-8q4r-r495",
            "id": "GHSA-v6rf-8q4r-r495",
            "imported": "2026-07-31T17:07:26.589Z",
            "modified": "2026-07-24T18:31:41Z",
            "published": "2026-07-24T18:31:30Z",
            "url": "https://api.github.com/advisories/GHSA-v6rf-8q4r-r495"
        },
        {
            "html_url": "https://euvd.enisa.europa.eu/vulnerability/EUVD-2026-48722",
            "id": "EUVD-2026-48722",
            "imported": "2026-07-31T17:07:23.798Z",
            "modified": "2026-07-28T01:06:26Z",
            "published": "2026-07-24T16:45:24Z",
            "url": "https://euvdservices.enisa.europa.eu/api/enisaid?id=EUVD-2026-48722"
        }
    ]
}

References

Affected packages

Julia / LibSSH2_jll

Package

Name: LibSSH2_jll
Purl: pkg:julia/LibSSH2_jll?uuid=29816b5a-b9ab-546f-933c-edad1886dfa8

Affected ranges

Type: SEMVER
Events: Introduced

0 Unknown introduced version / All previous versions are affected

Fixed

1.11.104+0

Database specific

source

"https://github.com/JuliaLang/SecurityAdvisories.jl/tree/generated/osv/2026/JLSEC-2026-1088.json"