Widely-used library (libssh2) with remote memory disclosure risk; could disrupt services across multiple products.
CVE-2025-15661
libssh2 <=1.11.1: heap over-read via SFTP NAME can leak memory or crash
Is CVE-2025-15661 being exploited?
Not confirmed. CVE-2025-15661 does not appear in CISA's Known Exploited Vulnerabilities catalog, which records only exploitation that has been observed and reported publicly. That is evidence of absence of a report, not evidence the flaw is unattacked. EPSS currently estimates a 0.65% probability of exploitation in the next 30 days.
How severe is CVE-2025-15661?
CVE-2025-15661 is rated High with a CVSS score of 8.3. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.
Is there a patch for CVE-2025-15661?
Yes. A fix has been recorded for CVE-2025-15661. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2025-15661 affect?
CVE-2025-15661 affects libssh2 <= 1.11.1. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2025-15661?
Upgrade to fixed libssh2 release
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Remote heap over-read via crafted SSH_FXP_NAME in SFTP (READLINK/REALPATH) can leak memory or crash
Immediate action required
- affected<= 1.11.1
As published in the CVE Program record. A version outside these ranges is not a statement that it is unaffected — vendors sometimes understate a range, and distribution-backported builds carry upstream numbers that do not reflect what was patched into them.