Heap Buffer Over-read in libssh2 sftp_symlink()
CVE-2025-15661 is an out-of-bounds heap read vulnerability in libssh2 through version 1.11.1, in the sftp_symlink() function in src/sftp.c. The flaw is triggered when libssh2 processes a crafted SSH_FXP_NAME response during SFTP READLINK or REALPATH operations. A malicious SSH server or a man-in-the-middle attacker can provide a link_len value larger than the actual packet data, and because the code does not properly validate the available packet buffer size before a memcpy operation, libssh2 performs a heap buffer over-read of up to target_len minus one bytes. This can expose adjacent heap memory contents and may also crash the client application.
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Impact, mitigation & remediation
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Impact
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Mitigation
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Remediation
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Exploits
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No public exploit code observed for this vulnerability.
Affected products & vendors
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Vendor-confirmed product mapping. Mallory continuously reconciles this list against your asset inventory.
Recent activity
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The version that knows your environment.
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Every observed campaign linking this CVE to a named adversary.
Malware families riding this exploit, with evidence and IOCs.
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Cross-references every affected SKU, including bundled OEM variants.
Community discussion across Reddit, Mastodon, and other social sources.