OESA-2026-3014 (CVE-2025-15661)
Vulnerability from osv_openeuler – Published: 2026-07-19 11:11 – Updated: 2026-08-06 11:11 – Source websitelibssh2 is a library implementing the SSH2 protocol as defined by Internet Drafts: SECSH-TRANS(22), SECSH-USERAUTH(25), SECSH-CONNECTION(23), SECSH-ARCH(20), SECSH-FILEXFER(06)*, SECSH-DHGEX(04), and SECSH-NUMBERS(10).
Security Fix(es):
libssh2 through 1.11.1, fixed in commit 2dae302, contains an out-of-bounds heap read vulnerability in the sftp_symlink() function in src/sftp.c that allows a malicious SSH server or man-in-the-middle attacker to disclose heap memory contents or cause a crash by sending a crafted SSH_FXP_NAME response. Attackers can supply a link_len value larger than the actual packet data in SSH_FXP_NAME responses for SFTP READLINK and REALPATH operations, triggering a heap buffer over-read of up to target_len minus one bytes due to the missing validation of available packet buffer size before the memcpy operation.(CVE-2025-15661)
libssh2 through 1.11.1, fixed in commit 1762685, contains a pre-authentication denial of service vulnerability in the SSH_MSG_EXT_INFO handler in src/packet.c that allows a malicious SSH server to cause a client CPU exhaustion loop by sending a crafted extension count value. A malicious server can set nr_extensions to 0xFFFFFFFF during key exchange, causing the client to spin in a tight CPU loop for over 60 seconds because return values from _libssh2_get_string() are unchecked and the session timeout does not apply to CPU-bound loops.(CVE-2026-55199)
| URL | Type | |
|---|---|---|
{
"affected": [
{
"ecosystem_specific": {
"aarch64": [
"libssh2-1.10.0-10.oe2203sp4.aarch64.rpm",
"libssh2-debuginfo-1.10.0-10.oe2203sp4.aarch64.rpm",
"libssh2-debugsource-1.10.0-10.oe2203sp4.aarch64.rpm",
"libssh2-devel-1.10.0-10.oe2203sp4.aarch64.rpm"
],
"noarch": [
"libssh2-help-1.10.0-10.oe2203sp4.noarch.rpm"
],
"src": [
"libssh2-1.10.0-10.oe2203sp4.src.rpm"
],
"x86_64": [
"libssh2-1.10.0-10.oe2203sp4.x86_64.rpm",
"libssh2-debuginfo-1.10.0-10.oe2203sp4.x86_64.rpm",
"libssh2-debugsource-1.10.0-10.oe2203sp4.x86_64.rpm",
"libssh2-devel-1.10.0-10.oe2203sp4.x86_64.rpm"
]
},
"package": {
"ecosystem": "openEuler:22.03-LTS-SP4",
"name": "libssh2",
"purl": "pkg:rpm/openEuler/libssh2\u0026distro=openEuler-22.03-LTS-SP4"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "1.10.0-10.oe2203sp4"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"database_specific": {
"severity": "High"
},
"details": "libssh2 is a library implementing the SSH2 protocol as defined by Internet Drafts: SECSH-TRANS(22), SECSH-USERAUTH(25), SECSH-CONNECTION(23), SECSH-ARCH(20), SECSH-FILEXFER(06)*, SECSH-DHGEX(04), and SECSH-NUMBERS(10).\r\n\r\nSecurity Fix(es):\n\nlibssh2 through 1.11.1, fixed in commit 2dae302, contains an out-of-bounds heap read vulnerability in the sftp_symlink() function in src/sftp.c that allows a malicious SSH server or man-in-the-middle attacker to disclose heap memory contents or cause a crash by sending a crafted SSH_FXP_NAME response. Attackers can supply a link_len value larger than the actual packet data in SSH_FXP_NAME responses for SFTP READLINK and REALPATH operations, triggering a heap buffer over-read of up to target_len minus one bytes due to the missing validation of available packet buffer size before the memcpy operation.(CVE-2025-15661)\n\nlibssh2 through 1.11.1, fixed in commit 1762685, contains a pre-authentication denial of service vulnerability in the SSH_MSG_EXT_INFO handler in src/packet.c that allows a malicious SSH server to cause a client CPU exhaustion loop by sending a crafted extension count value. A malicious server can set nr_extensions to 0xFFFFFFFF during key exchange, causing the client to spin in a tight CPU loop for over 60 seconds because return values from _libssh2_get_string() are unchecked and the session timeout does not apply to CPU-bound loops.(CVE-2026-55199)",
"id": "OESA-2026-3014",
"modified": "2026-08-06T11:11:54Z",
"published": "2026-07-19T11:11:54Z",
"references": [
{
"type": "ADVISORY",
"url": "https://www.openeuler.org/zh/security/security-bulletins/detail/?id=openEuler-SA-2026-3014"
},
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2025-15661"
},
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-55199"
}
],
"schema_version": "1.7.2",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
"type": "CVSS_V3"
}
],
"summary": "libssh2 security update",
"upstream": [
"CVE-2025-15661",
"CVE-2026-55199"
]
}
Sightings
| Author | Source | Type | Date | Other |
|---|
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