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Vulnerabilities

Vulnerability · CVE-2025-15661

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 o

Published Jun 18, 2026 · catalog updated Oct 21, 2026 · libssh2 through 1.11.1, fixed

Check if you run it

No confirmed exploitation is on record for CVE-2025-15661. EPSS is 0.65%. Act only if a listed version of libssh2 through 1.11.1, fixed is installed.

Gaps on this record

  • The stored product name is a package slug. The name on this page is taken from the title (libssh2 through 1.11.1, fixed).
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
Severity
Medium6.5
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.65%
Remediation
Advisory link
Affected products
Alpine:v3.21 libssh2 · Alpine:v3.22 libssh2 · Alpine:v3.23 libssh2 · Alpine:v3.24 libssh2 · Alpine:v3.24 rust

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.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • Alpine:v3.21 libssh20 → 1.11.1-r3
  • Alpine:v3.22 libssh20 → 1.11.1-r3
  • Alpine:v3.23 libssh20 → 1.11.1-r4
  • Alpine:v3.24 libssh20 → 1.11.1-r4
  • Alpine:v3.24 rust0 → 1.96.1-r0

How to fix CVE-2025-15661

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2025-15661. EPSS is 0.65%. Act only if a listed version of libssh2 through 1.11.1, fixed is installed.

Which versions are affected?

Compare what you have installed with 0 → 1.11.1-r3, 0 → 1.11.1-r4, 0 → 1.96.1-r0. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

No weakness class is stored. EPSS 0.65%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

No public source repository is identified for this product.

Timeline

Detection, updates, and resolution for this record.

  1. Jun 18, 2026 · OpenSSF OSV / OSV Scanner

    Detected

    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 response

  2. Oct 20, 2026 · OpenSSF OSV / OSV Scanner

    Fix available

    libssh2 fixed in 1.11.1-r4; rust fixed in 1.96.1-r0

  3. Oct 20, 2026 · OpenSSF OSV / OSV Scanner

    Fix available

    libssh2 fixed in 1.11.1-r4

  4. Oct 20, 2026 · OpenSSF OSV / OSV Scanner

    Fix available

    rust fixed in 1.96.1-r0

  5. Oct 20, 2026 · OpenSSF OSV / OSV Scanner

    Updated

    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 response

  6. Oct 21, 2026 · OpenSSF OSV / OSV Scanner

    Fix available

    libssh2 fixed in 1.11.1-r3; libssh2 fixed in 1.11.1-r3; libssh2 fixed in 1.11.1-r4; libssh2 fixed in 1.11.1-r4

  7. Oct 21, 2026 · OpenSSF OSV / OSV Scanner

    Fix available

    libssh2 fixed in 1.11.1-r3

  8. Oct 21, 2026 · OpenSSF OSV / OSV Scanner

    Updated

    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 response

Sources

  • CVE.orgVulnerability recordCVE-2025-15661

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2025-15661

    30-day exploitation probability 0.65%

    first.org
  • OpenSSF OSV / OSV ScannerPackage advisoryALPINE-CVE-2025-15661
    osv.dev
  • Trivy Vulnerability DBPackage advisoryALPINE-CVE-2025-15661

    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

    osv.dev

References

Freshness

Last verified in this catalog Oct 24, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.